Introduction to Psychology
G AT E WAYS TO M I N D A N D B E H AV I O R TWELFTH EDITION
Dennis Coon
John O. Mitterer
Brock University
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Introduction to Psychology: Gateways to Mind
and Behavior, Twelfth Edition
Dennis Coon / John O. Mitterer
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about the authors
After earning a doctorate in psychology from the University of Arizona, Dennis Coon taught
for 22 years at Santa Barbara City College, California. Throughout his career, Dr. Coon has
especially enjoyed the challenge of teaching introductory psychology. He and his wife, Sevren,
have returned to Tucson, where he continues to teach, write, edit, and consult.
Dr. Coon is the author of Introduction to Psychology and Psychology: A Journey, as well as
Psychology: Modules for Active Learning. Together, these texts have been used by more than
2 million students. Dr. Coon frequently serves as a reviewer and consultant to publishers, and
he edited the best-selling trade book Choices. He also helped design modules for PsychNow!,
Wadsworth’s interactive CD-ROM.
In his leisure hours, Dr. Coon enjoys hiking, photography, painting, woodworking, and
music. He also designs, builds, and plays classical and steel string acoustic guitars. He has published articles on guitar design and occasionally offers lectures on this topic, in addition to his
more frequent presentations on psychology.
John O. Mitterer was awarded his Ph.D. in cognitive psychology from McMaster University.
Currently, Dr. Mitterer teaches at Brock University, where he has taught more than 20,000 introductory psychology students. He is the recipient of the 2003 Brock University Distinguished
Teaching Award, a 2003 Ontario Confederation of University Faculty Associations (OCUFA)
Teaching Award, a 2004 National 3M Teaching Fellowship, and the 2005 Canadian
Psychological Association Award for Distinguished Contributions to Education and Training
in Psychology.
Dr. Mitterer’s primary research focus is on basic cognitive processes in learning and teaching.
He consulted for a variety of companies, such as Bell Northern Research, Unisys Corporation,
IBM Canada, and computer-game developer Silicon Knights. His professional focus, however,
is on applying cognitive principles to the improvement of undergraduate education. In support
of his introductory psychology course, he has been involved in the production of textbooks
and ancillary materials such as CD-ROMs and websites for both students and instructors. Dr.
Mitterer has published and lectured on undergraduate instruction throughout Canada and the
United States.
In his spare time, Dr. Mitterer strives to become a better golfer and to attain his life goal of
seeing all the bird species in the world. To this end he recently traveled to Papua New Guinea,
Brazil, Australia, and South Africa.
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brief contents
Introduction: The Psychology of Studying
1
1
Introduction to Psychology and Research Methods
11
Psychology in Action: Psychology in the Media — Separating Fact from Fiction 43
2
Brain and Behavior
47
Psychology in Action: Handedness — Are You Dexterous or Sinister? 73
3
Human Development
78
Psychology in Action: Effective Parenting — Raising Healthy Children 112
4
Sensation and Reality
118
Psychology in Action: Controlling Pain — This Won’t Hurt a Bit 145
5
Perceiving the World
149
Psychology in Action: Perception and Objectivity — Believing Is Seeing 176
6
States of Consciousness
181
Psychology in Action: Exploring and Using Dreams 212
7
Conditioning and Learning
218
Psychology in Action: Behavioral Self-Management — A Rewarding Project 247
8
Memory
251
Psychology in Action: Mnemonics — Memory Magic 279
9
Cognition, Language, Creativity, and Intelligence
283
Psychology in Action: Culture, Race, IQ, and You 314
10
Motivation and Emotion
319
Psychology in Action: Emotional Intelligence — The Fine Art of Self-Control 353
v
vi
Brief Contents
11
Gender and Sexuality
357
Psychology in Action: When Pleasure Fades — Sexual Problems 381
12
Personality
388
Psychology in Action: Barriers and Bridges — Understanding Shyness 420
13
Health, Stress, and Coping
425
Psychology in Action: Stress Management 453
14
Psychological Disorders
459
Psychology in Action: Suicide — Lives on the Brink 490
15
Therapies
495
Psychology in Action: Self-Management and Finding Professional Help 522
16
Social Thinking and Social Influence
529
Psychology in Action: Assertiveness Training — Standing Up for Your Rights 551
17
Prosocial and Antisocial Behavior
556
Psychology in Action: Multiculturalism — Living with Diversity 579
18
Applied Psychology
584
Psychology in Action: Human Factors Psychology — Who’s the Boss Here? 607
Appendix: Behavioral Statistics 612
Glossary G-1
References R-1
Name Index N-1
Subject Index S-1
contents
Introduction: The Psychology
of Studying 1
The SQ4R Method — How to Tame a Textbook 2
How to Use Introduction to Psychology: Gateways to Mind
and Behavior 3
Effective Note-Taking — Good Students, Take
Note! 3
Using and Reviewing Your Notes 4
Study Strategies — Making a Habit of Success 4
Self-Regulated Learning — Academic All-Stars 5
Procrastination — Avoiding the Last-Minute
Blues 6
Time Management 6
Goal Setting 6
Make Learning an Adventure 7
Taking Tests — Are You “Test Wise”? 7
General Test-Taking Skills 7
Using Digital Media — Netting New Knowledge 8
Digital Gateways 8
The Book Companion Website 8
CengageNOW 9
Wadsworth’s Psychology Resource Center 9
Psychology Websites 9
A Final Word 10
WEB RESOURCES 10
INTERACTIVE LEARNING 10
1 Introduction to Psychology
and Research Methods 11
A Brief History of Psychology — Psychology’s
Family Album 22
Structuralism 22
Functionalism 22
Behaviorism 23
Gestalt Psychology 24
Psychoanalytic Psychology 24
Humanistic Psychology 25
The Role of Women in Psychology’s Early Days 26
Psychology Today — Three Complementary
Perspectives on Behavior 26
The Biological Perspective 27
The Psychological Perspective 27
The Sociocultural Perspective 28
Psychologists — Guaranteed Not to Shrink 29
Other Mental Health Professionals 31
The Profession of Psychology 31
Specialties in Psychology 32
The Psychology Experiment — Where Cause
Meets Effect 32
Variables and Groups 33
Evaluating Results 34
Double Blind — On Placebos and Self-Fulfilling
Prophecies 35
Research Participant Bias 35
Researcher Bias 36
Nonexperimental Research Methods — Different
Strokes 37
Naturalistic Observation 37
Correlational Studies 38
The Clinical Method — One Case At A Time 40
Survey Method — Here, Have a Sample 40
Preview: Wondering About Human
Behavior 12
PSYCHOLOGY IN ACTION:
Psychology in the Media — Separating Fact from
Fiction 43
Psychology — The ABCs of Behavior 12
CHAPTER IN REVIEW 45
Seeking Empirical Evidence 12
Psychological Research 14
Research Specialties 14
Psychology’s Goals 15
Critical Thinking — Take It With a Grain of Salt 16
Thinking About Behavior 16
Pseudopsychologies — Palms, Planets, and
Personality 17
Problems in the Stars 18
Scientific Research — How to Think Like a
Psychologist 19
The Scientific Method 19
WEB RESOURCES 46
INTERACTIVE LEARNING 46
FEATURE BOXES (HIGHLIGHTS)
• CRITICAL THINKING: Testing Common-Sense
Beliefs 13
• DISCOVERING PSYCHOLOGY: Is a Career in
Psychology Right for You? 31
• CRITICAL THINKING: That’s Interesting, but Is It
Ethical? 34
• HUMAN DIVERSITY: Is There a Gender Bias in
Psychological Research? 42
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Contents
2 Brain and Behavior
The Newborn — More Than Meets the Eye 85
47
Preview: Finding Music in Walnut Grapefruit
Tofu 48
Neurons — Building a “Biocomputer” 48
Parts of a Neuron 48
The Nerve Impulse 48
Synapses and Neurotransmitters 51
Neural Networks 52
Perceptual and Cognitive Development 85
Motor Development 87
Emotional Development 87
Social Development — Baby, I’m Stuck on You 89
Attachment 89
Day Care 90
Attachment and Affectional Needs 91
Parental Influences — Life with Mom and Dad 91
The Nervous System — Wired for Action 53
Research Methods — Charting the Brain’s Inner
Realms 56
Mapping Brain Structure 56
Exploring Brain Function 57
The Cerebral Cortex — My, What a Big Brain You
Have! 59
Cerebral Hemispheres 60
Hemispheric Specialization 60
Lobes of the Cerebral Cortex 63
The Subcortex — At the Core of the (Brain)
Matter 67
The Hindbrain 67
The Forebrain 68
The Magnificent Brain 70
The Endocrine System — My Hormones Made Me
Do It 70
PSYCHOLOGY IN ACTION:
Handedness — Are You Dexterous or Sinister? 73
CHAPTER IN REVIEW 76
Parenting Styles 91
Maternal and Paternal Influences 92
Ethnic Differences: Four Flavors of Parenting 93
Language Development — Fast-Talking Babies 94
Language and the Terrible Twos 94
The Roots of Language 95
Cognitive Development — Think Like a Child 97
Piaget’s Theory of Cognitive Development 97
Piaget Today 99
Vygotsky’s Sociocultural Theory 101
Adolescence and Young Adulthood — The Best
of Times, the Worst of Times 102
Puberty 102
The Search for Identity 103
The Transition to Adulthood 104
Moral Development — Growing a Conscience 104
Levels of Moral Development 105
The Story of a Lifetime — Rocky Road or Garden
Path? 106
Erikson’s Psychosocial Theory 106
Later Adulthood: Will You Still Need Me When
I’m 64? 108
WEB RESOURCES 77
INTERACTIVE LEARNING 77
A Midlife Crisis? 108
Old Age 109
FEATURE BOXES (HIGHLIGHTS)
• CRITICAL THINKING: You Can Change Your Mind, but
Can You Change Your Brain? 53
Death and Dying — The Final Challenge 110
• CRITICAL THINKING: Repairing Your Brain 56
PSYCHOLOGY IN ACTION:
Effective Parenting — Raising Healthy Children 112
• THE CLINICAL FILE: A Stroke of Bad Luck 61
• CRITICAL THINKING: Mirror, Mirror in the Brain 65
• HUMAN DIVERSITY: His and Hers Brains? 66
3 Human Development
CHAPTER IN REVIEW 115
WEB RESOURCES 117
INTERACTIVE LEARNING 117
FEATURE BOXES (HIGHLIGHTS)
78
Preview: It’s A Girl! 79
Nature and Nurture — It Takes Two to Tango 79
Heredity 79
Environment 81
Reaction Range 84
Reactions to Impending Death 111
• DISCOVERING PSYCHOLOGY: What’s Your
Attachment Style? 91
• HUMAN DIVERSITY: Ethnic Diversity and Identity 103
• CRITICAL THINKING: The Twixters 104
Contents
4 Sensation and Reality
118
5 Perceiving the World
Preview: Can’t You Hear the Bats? 119
Preview: Murder! 150
Psychophysics — The Limits of Sensibility 119
Perception: That Extra Step 150
Transduction 119
Absolute Thresholds 119
Difference Thresholds 120
Sensory Analysis and Coding 121
Vision — Catching Some Rays 123
Structure of the Eye 124
Rods and Cones 125
Color Vision — There’s More to It Than Meets the
Eye 127
Color Theories 128
Color Blindness and Color Weakness 129
Dark Adaptation — Let There Be Light! 131
Hearing — Good Vibrations 132
How We Hear Sounds 133
Smell and Taste — The Nose Knows When the
Tongue Can’t Tell 135
The Sense of Smell 136
Taste and Flavors 137
The Somesthetic Senses — Flying by the Seat of
Your Pants 138
The Skin Senses 139
The Vestibular System 140
Adaptation, Attention, and Gating — Tuning In
and Tuning Out 142
Sensory Adaptation 142
Selective Attention 142
Sensory Gating 143
PSYCHOLOGY IN ACTION:
Controlling Pain —This Won’t Hurt a Bit 145
149
Bottom-Up and Top-Down Processing 151
Perception and Attention — May I Have Your . . .
Attention! 151
Inattentional Blindness 153
Habituation 153
Motives, Emotions, and Perception 153
Perceptual Organization — Getting It All
Together 154
Gestalt Principles 154
Perceptual Constancies — Taming an Unruly
World 157
Depth Perception — What If the World Were
Flat? 159
Binocular Depth Cues 160
Monocular Depth Cues 162
Perceptual Learning — What If the World Were
Upside Down? 165
Perceptual Habits 166
The Context of Perception 168
Illusions 168
Perceptual Expectancies — On Your Mark, Get
Set 171
Extrasensory Perception — Do You Believe in
Magic? 172
An Appraisal of ESP 173
Stage ESP 174
PSYCHOLOGY IN ACTION:
Perception and Objectivity — Believing Is Seeing 176
CHAPTER IN REVIEW 178
CHAPTER IN REVIEW 147
WEB RESOURCES 179
WEB RESOURCES 148
INTERACTIVE LEARNING 180
INTERACTIVE LEARNING 148
FEATURE BOXES (HIGHLIGHTS)
FEATURE BOXES (HIGHLIGHTS)
• THE CLINICAL FILE: Pay Attention! 152
• CRITICAL THINKING: Subliminal Seduction or
Subliminal Myth? 121
• CRITICAL THINKING: The “Boiled Frog
Syndrome” 154
• BRAINWAVES: Blindsight: The “What” and the “Where”
of Vision 127
• CRITICAL THINKING: A Bird’s-Eye View 158
• DISCOVERING PSYCHOLOGY: Are You ColorBlind? 130
• THE CLINICAL FILE: Staying in Touch with Reality 169
• DISCOVERING PSYCHOLOGY: Going Biosonar 132
• BRAINWAVES: The Matrix: Do Phantoms Live
Here? 145
• HUMAN DIVERSITY: Do They See What We See? 167
ix
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Contents
6 States of Consciousness
181
PSYCHOLOGY IN ACTION:
Exploring and Using Dreams 212
Preview: A Visit to Several States
(of Consciousness) 182
CHAPTER IN REVIEW 215
States of Consciousness — The Many Faces of
Awareness 182
INTERACTIVE LEARNING 217
Altered States of Consciousness 182
Sleep — A Nice Place to Visit 182
The Need for Sleep 183
Sleep Patterns 184
Stages of Sleep — The Nightly Roller-Coaster 185
Sleep Stages 186
The Dual Process Hypothesis of Sleep 186
Sleep Disturbances — Showing Nightly: Sleep
Wars! 189
Insomnia 189
Sleepwalking, Sleeptalking, and Sleepsex 190
Nightmares and Night Terrors 190
Sleep Apnea 191
Narcolepsy 192
Dreams — A Separate Reality? 192
REM Sleep Revisited 192
Dream Theories 192
Dream Worlds 193
Hypnosis — Look into My Eyes 194
Theories of Hypnosis 194
The Reality of Hypnosis 195
Stage Hypnosis 196
Meditation and Sensory Deprivation — Chilling,
the Healthy Way 197
Meditation 197
Sensory Deprivation 198
Positive Psychology: Mindfulness and Well-Being 199
Drug-Altered Consciousness — the High and Low
of It 199
Drug Dependence 200
Patterns of Abuse 200
Uppers — Amphetamines, Cocaine, MDMA,
Caffeine, Nicotine 201
Cocaine 203
MDMA (“Ecstasy”) 204
Caffeine 204
Nicotine 205
Downers — Sedatives, Tranquilizers, and
Alcohol 206
Barbiturates 206
GHB 206
Tranquilizers 207
Alcohol 207
Hallucinogens — Tripping the Light Fantastic 210
LSD and PCP 210
Marijuana 210
WEB RESOURCES 216
FEATURE BOXES (HIGHLIGHTS)
• CRITICAL THINKING: What Is It Like To Be a Bat? 183
• HUMAN DIVERSITY: Consciousness and Culture 184
• CRITICAL THINKING: They Came from Outer
Space? 188
• DISCOVERING PSYCHOLOGY: Swinging
Suggestions 195
• BRAINWAVES: How Psychoactive Drugs Affect the
Brain 201
7 Conditioning and Learning
218
Preview: Rats! 219
What Is Learning — Does Practice Make
Perfect? 219
Types of Learning 219
Classical Conditioning — Does the Name Pavlov
Ring a Bell? 220
Pavlov’s Experiment 220
Principles of Classical Conditioning — Here’s
Johnny 222
Acquisition 222
Expectancies 222
Extinction and Spontaneous Recovery 223
Generalization 223
Discrimination 224
Classical Conditioning in Humans — An Emotional
Topic 224
Conditioned Emotional Responses 224
Vicarious, or Secondhand, Conditioning 225
Operant Conditioning — Can Pigeons Play PingPong? 226
Positive Reinforcement 226
Acquiring an Operant Response 226
The Timing of Reinforcement 227
Shaping 228
Operant Extinction 228
Negative Reinforcement 229
Punishment 229
Operant Reinforcers — What’s Your Pleasure? 230
Primary Reinforcers 230
Secondary Reinforcers 230
Feedback 232
Learning Aids 232
Contents
Partial Reinforcement — Las Vegas, a Human
Skinner Box? 234
Schedules of Partial Reinforcement 235
Stimulus Control — Red Light, Green Light 236
Punishment — Putting the Brakes on
Behavior 238
Variables Affecting Punishment 238
The Downside of Punishment 239
Using Punishment Wisely 240
Cognitive Learning — Beyond Conditioning 241
Cognitive Maps 242
Latent Learning 242
Modeling — Do as I Do, Not as I Say 243
Observational Learning 243
Modeling and the Media 244
PSYCHOLOGY IN ACTION:
Behavioral Self-Management — A Rewarding Project 247
CHAPTER IN REVIEW 249
Forgetting in LTM — Why We, uh, Let’s See; Why
We, uh . . . Forget! 264
When Encoding Fails 265
When Memory Storage Fails 266
When Retrieval Fails 266
Memory and the Brain — Some “Shocking”
Findings 270
Consolidation 270
Long-Term Memory and the Brain 272
Exceptional Memory — Wizards of Recall 273
Eidetic Imagery 273
A Case of Photographic Memory 274
Memory Champions 275
Improving Memory — Keys to the Memory
Bank 275
Encoding Strategies 276
Retrieval Strategies 277
A Look Ahead 278
WEB RESOURCES 250
PSYCHOLOGY IN ACTION:
Mnemonics — Memory Magic 279
INTERACTIVE LEARNING 250
CHAPTER IN REVIEW 281
FEATURE BOXES (HIGHLIGHTS)
WEB RESOURCES 282
• THE CLINICAL FILE: Coping with Chemo 221
INTERACTIVE LEARNING 282
• BRAINWAVES: Tickling Your Own Fancy 230
FEATURE BOXES (HIGHLIGHTS)
• DISCOVERING PSYCHOLOGY: Learning and
Conservation 233
• HUMAN DIVERSITY: Cows, Memories, and
Culture 254
• CRITICAL THINKING: Are Animals Stuck in Time? 236
• CRITICAL THINKING: Do You Like Jam with Your
Memory? 257
• CRITICAL THINKING: You Mean Video Games Might
Be Bad for Me? 245
8 Memory
251
• CRITICAL THINKING: Telling Wrong from Right in
Forensic Memory 258
• DISCOVERING PSYCHOLOGY: Card Magic! 265
Preview: “What the Hell’s Going on Here?” 252
• THE CLINICAL FILE: The Recovered Memory/False
Memory Debate 269
Stages of Memory — Do You Have a Mind Like a
Steel Trap? Or a Sieve? 252
• BRAINWAVES: The Long-Term Potential of a Memory
Pill 273
Sensory Memory 252
Short-Term Memory 253
Long-Term Memory 253
Short-Term Memory — Do You Know the Magic
Number? 255
Chunking 255
Rehearsing Information 255
Long-Term Memory — Where the Past Lives 256
Constructing Memories 256
Organizing Memories 259
Skill Memory and Fact Memory 260
Measuring Memory — The Answer Is on the Tip of
My Tongue 261
Recalling Information 262
Recognizing Information 262
Relearning Information 263
Implicit and Explicit Memories 263
9 Cognition, Language, Creativity,
and Intelligence 283
Preview: Homo Sapiens 284
What Is Thinking? — Brains over Brawn 284
Some Basic Units of Thought 284
Mental Imagery — Does a Frog Have Lips? 284
The Nature of Mental Images 285
Concepts — I’m Positive, It’s a
Whatchamacallit 286
Forming Concepts 286
Types of Concepts 287
Language — Don’t Leave Home without It 288
The Structure of Language 290
The Animal Language Debate 291
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Contents
Problem Solving — Getting an Answer in
Sight 293
Mechanical Solutions 293
Solutions by Understanding 293
Heuristics 293
Insightful Solutions 294
Common Barriers to Problem Solving 297
Creative Thinking — Down Roads Less
Traveled 297
Tests of Creativity 298
Stages of Creative Thought 299
Positive Psychology: The Creative Personality 300
Living More Creatively 301
Intuitive Thought — Mental Shortcut? Or
Dangerous Detour? 301
Intuition 301
Framing 303
Wisdom 303
Human Intelligence — The IQ and You 304
Defining Intelligence 304
Intelligence Tests 305
Intelligence Quotients 305
The Wechsler Tests 307
Group Tests 307
Variations in Intelligence — Curved Like a
Bell 308
The Mentally Gifted 308
Intellectual Disability 309
Questioning Intelligence — How Intelligent Are
Intelligence Tests? 310
Multiple Intelligences 310
Artificial Intelligence: I Compute, Therefore I Am 311
Heredity, Environment, and Intelligence 312
PSYCHOLOGY IN ACTION:
Culture, Race, IQ, and You 314
CHAPTER IN REVIEW 317
WEB RESOURCES 318
INTERACTIVE LEARNING 318
FEATURE BOXES (HIGHLIGHTS)
• HUMAN DIVERSITY: Bilingualism — Si o No, Oui ou
Non, Yes or No? 289
• HUMAN DIVERSITY: How to Weigh an Elephant 296
• CRITICAL THINKING: Have You Ever Thin Sliced Your
Teacher? 302
• HUMAN DIVERSITY: Intelligence — How Would a Fool
Do It? 304
• THE CLINICAL FILE: Meet the Rain Man 309
• CRITICAL THINKING: You Mean Video Games Might
Be Good for Me? 313
10 Motivation and Emotion
319
Preview: Moved by the Music of Life 320
Motivation — Forces That Push and Pull 320
A Model of Motivation 320
Biological Motives and Homeostasis 321
Circadian Rhythms 322
Hunger — Pardon Me, My Hypothalamus Is
Growling 324
Internal Factors in Hunger 324
Brain Mechanisms 324
External Factors in Hunger and Obesity 326
Dieting 328
Eating Disorders 328
Culture, Ethnicity, and Dieting 331
Biological Motives Revisited — Thirst, Sex, and
Pain 331
Thirst 331
Pain 331
The Sex Drive 332
Stimulus Drives — Skydiving, Horror Movies, and
the Fun Zone 333
Arousal Theory 333
Levels of Arousal 334
Coping with Test Anxiety 335
Learned Motives — The Pursuit of Excellence 336
Opponent-Process Theory 336
Social Motives 336
The Need for Achievement 336
The Key to Success? 337
Motives in Perspective — A View from the
Pyramid 338
Intrinsic and Extrinsic Motivation 339
Turning Play into Work 339
Inside an Emotion — How Do You Feel? 341
Primary Emotions 341
Emotion and the Brain 342
Physiology and Emotion — Arousal, Sudden
Death, and Lying 343
Fight or Flight 343
Lie Detectors 344
Expressing Emotions — Making Faces and
Talking Bodies 346
Facial Expressions 346
Theories of Emotion — Several Ways to Fear a
Bear 348
The James-Lange Theory 348
The Cannon-Bard Theory 349
Schachter’s Cognitive Theory of Emotion 349
Emotional Appraisal 350
The Facial Feedback Hypothesis 350
A Contemporary Model of Emotion 352
Contents
PSYCHOLOGY IN ACTION:
Emotional Intelligence —The Fine Art of Self-Control 353
CHAPTER IN REVIEW 355
HIV/AIDS 379
Behavioral Risk Factors 379
Risk and Responsibility 380
WEB RESOURCES 356
INTERACTIVE LEARNING 356
PSYCHOLOGY IN ACTION:
When Pleasure Fades — Sexual Problems 381
FEATURE BOXES (HIGHLIGHTS)
• BRAINWAVES: Your Brain’s “Fat Point” 326
• DISCOVERING PSYCHOLOGY: What’s Your BMI?
(We’ve Got Your Number) 327
• DISCOVERING PSYCHOLOGY: Behavioral
Dieting 329
• HUMAN DIVERSITY: Xtreme! 334
• CRITICAL THINKING: To Catch a Terrorist 345
• CRITICAL THINKING: Crow’s-Feet and Smiles
Sweet 347
• THE CLINICAL FILE: Suppressing Emotion — Don’t
Turn Off the Music 351
11 Gender and Sexuality
STDs and Safer Sex — Choice, Risk, and
Responsibility 378
357
CHAPTER IN REVIEW 386
WEB RESOURCES 387
INTERACTIVE LEARNING 387
FEATURE BOXES (HIGHLIGHTS)
• THE CLINICAL FILE: Bruce or Brenda — Can Sex Be
Assigned? 360
• BRAINWAVES: Genes, the Brain, and Sexual
Orientation 362
• HUMAN DIVERSITY: High Test 365
• CRITICAL THINKING: Are We Oversexualizing Young
Girls? 376
• CRITICAL THINKING: Gender Role Stereotyping and
Rape 377
Preview: Pink and Blue 358
Sexual Development — Circle One: XX or XY? 358
Dimensions of Sex 358
Sexual Orientation — Who Do You Love? 361
Homosexuality 361
Gender Development — Circle One: Masculine or
Feminine 363
Gender Identity 364
Gender Roles 364
Gender Role Socialization 366
Androgyny — Are You Masculine, Feminine, or
Androgynous? 367
Psychological Androgyny 367
Sexual Behavior — Mapping the Erogenous
Zones 369
Sexual Arousal 369
Human Sexual Response — Sexual
Interactions 371
Comparing Male and Female Responses 372
Atypical Sexual Behavior — Trench Coats, Whips,
Leathers, and Lace 373
Paraphilias 373
Attitudes and Sexual Behavior — The Changing
Sexual Landscape 374
Is the Revolution Over? 375
The Crime of Rape 377
12 Personality
388
Preview: The Hidden Essence 389
The Psychology of Personality — Do You Have
Personality? 389
Traits 390
Do We Inherit Personality? 390
Types 391
Self-Concept 392
Personality Theories 393
The Trait Approach — Describe Yourself in
18,000 Words or Less 394
Predicting Behavior 394
Describing People 394
Classifying Traits 394
The Big Five 396
Traits, Consistency, and Situations 397
Psychoanalytic Theory — Id Came to Me in a
Dream 398
The Structure of Personality 398
The Dynamics of Personality 399
Personality Development 400
The Neo-Freudians 402
Learning Theories of Personality — Habit I Seen
You Before? 404
How Situations Affect Behavior 405
Personality Behavior 405
Social Learning Theory 406
Behavioristic View of Development 407
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Contents
Humanistic Theory — Peak Experiences and
Personal Growth 408
Maslow and Self-Actualization 409
Positive Psychology: Positive Personality Traits 410
Carl Rogers’ Self Theory 410
Humanistic View of Development 412
Personality Theories — Overview and
Comparison 413
Personality Assessment — Psychological
Yardsticks 414
Conflict — Yes, No, Yes, No, Yes, No, Well,
Maybe 438
Managing Conflicts 439
Psychological Defense — Mental Karate? 440
Learned Helplessness — Is There Hope? 442
Depression 443
Depression: Why Students Get the Blues 444
Coping with Depression 445
Stress and Health — Unmasking a Hidden
Killer 445
The Interview 414
Direct Observation and Rating Scales 415
Personality Questionnaires 416
Projective Tests of Personality — Inkblots and Hidden
Plots 418
Sudden Murderers — A Research Example 419
PSYCHOLOGY IN ACTION:
Barriers and Bridges — Understanding Shyness 420
Life Events and Stress 446
Psychosomatic Disorders 447
Biofeedback 448
The Cardiac Personality 450
Hardy Personality 451
Positive Psychology: Hardiness, Optimism, and
Happiness 452
The Value of Social Support 452
PSYCHOLOGY IN ACTION:
Stress Management 453
CHAPTER IN REVIEW 422
WEB RESOURCES 423
CHAPTER IN REVIEW 457
INTERACTIVE LEARNING 424
WEB RESOURCES 458
FEATURE BOXES (HIGHLIGHTS)
• CRITICAL THINKING: The Amazing Twins 391
INTERACTIVE LEARNING 458
FEATURE BOXES (HIGHLIGHTS)
• HUMAN DIVERSITY: Self-Esteem and
Culture — Hotshot or Team Player? 393
• DISCOVERING PSYCHOLOGY: What’s Your Musical
Personality? 395
• THE CLINICAL FILE: Perfectly Miserable 397
• DISCOVERING PSYCHOLOGY: Unhealthy Birds of a
Feather 429
• THE CLINICAL FILE: Burnout — The High Cost of
Caring 433
• THE CLINICAL FILE: Coping with Traumatic
Stress 435
• THE CLINICAL FILE: Telling Stories About
Ourselves 412
• HUMAN DIVERSITY: Acculturative Stress — Stranger
in a Strange Land 448
13 Health, Stress, and Coping
425
Preview: Jennifer’s Amazing Race 426
Health Psychology — Here’s to Your Good
Health 426
Behavioral Risk Factors 426
Health-Promoting Behaviors 427
Early Prevention 429
Community Health 430
Positive Psychology: Wellness 430
Stress — Thrill or Threat? 430
General Adaptation Syndrome 431
Stress, Illness, and Your Immune System 431
When Is Stress a Strain? 432
Appraising Stressors 433
Coping with Threat 434
Frustration — Blind Alleys and Lead Balloons 435
Reactions to Frustration 436
Coping with Frustration 437
• CRITICAL THINKING: It’s All in Your Mind 449
• DISCOVERING PSYCHOLOGY: Feeling Stressed?
You’ve Got a Friend 452
14 Psychological Disorders
459
Preview: Beware the Helicopters 460
Normality — What’s Normal? 460
Core Features of Disordered Behavior 462
Insanity 462
Classifying Mental Disorders — Problems by the
Book 463
An Overview of Psychological Disorders 464
General Risk Factors 466
Psychotic Disorders — The Dark Side of the
Moon 467
The Nature of Psychosis 468
Contents
Delusional Disorders — An Enemy Behind Every
Tree 470
Paranoid Psychosis 470
Schizophrenia — Shattered Reality 470
Disorganized Schizophrenia 471
Catatonic Schizophrenia 471
Paranoid Schizophrenia 472
Undifferentiated Schizophrenia 472
The Causes of Schizophrenia 472
Implications 476
Mood Disorders — Peaks and Valleys 476
Major Mood Disorders 477
What Causes Mood Disorders? 478
Anxiety-Based Disorders — When Anxiety
Rules 480
Adjustment Disorders 480
Anxiety Disorders 481
Obsessive-Compulsive Disorder 482
Stress Disorders 483
Dissociative Disorders 484
Somatoform Disorders 484
Anxiety and Disorder — Four Pathways to
Trouble 486
Psychodynamic Approach 486
Humanistic-Existential Approaches 486
Behavioral Approach 486
Cognitive Approach 487
Personality Disorders — Blueprints for
Maladjustment 487
Maladaptive Personality Patterns 487
Antisocial Personality 487
Disorders in Perspective — Psychiatric
Labeling 489
Social Stigma 489
A Look Ahead 490
PSYCHOLOGY IN ACTION:
Suicide — Lives on the Brink 490
CHAPTER IN REVIEW 493
WEB RESOURCES 494
INTERACTIVE LEARNING 494
FEATURE BOXES (HIGHLIGHTS)
• DISCOVERING PSYCHOLOGY: Crazy for a Day 461
• HUMAN DIVERSITY: Running Amok with Cultural
Maladies 466
• CRITICAL THINKING: Are the Mentally Ill Prone to
Violence? 473
15 Therapies
495
Preview: The Duck Syndrome 496
Psychotherapy — The Talking Cure 496
Dimensions of Therapy 496
Origins of Therapy — Bored Out of Your Skull 497
Psychoanalysis — Expedition into the
Unconscious 498
Psychoanalysis Today 499
Humanistic Therapies — Restoring Human
Potential 500
Client-Centered Therapy 500
Existential Therapy 501
Gestalt Therapy 501
Therapy at a Distance — Psych Jockeys and
Cybertherapy 502
Media Psychologists 502
Telephone Therapists 502
Internet Therapy 503
Behavior Therapy — Healing by Learning 503
Aversion Therapy 504
Desensitization 505
Operant Therapies — All the World Is a Skinner
Box? 508
Nonreinforcement and Extinction 508
Reinforcement and Token Economies 509
Cognitive Therapy — Think Positive! 510
Cognitive Therapy for Depression 510
Rational-Emotive Behavior Therapy 510
Group Therapy — People Who Need People 512
Psychodrama 512
Family and Couples Therapy 513
Group Awareness Training 513
Psychotherapy — An Overview 514
Core Features of Psychotherapy 514
The Future of Psychotherapy 515
Basic Counseling Skills 516
Medical Therapies — Psychiatric Care 518
Drug Therapies 518
Electrical Stimulation Therapy 519
Psychosurgery 519
Hospitalization 520
Community Mental Health Programs 521
PSYCHOLOGY IN ACTION:
Self-Management and Finding Professional Help 522
CHAPTER IN REVIEW 526
• BRAINWAVES: The Schizophrenic Brain 475
WEB RESOURCES 528
• THE CLINICAL FILE: Sick of Being Sick 484
INTERACTIVE LEARNING 528
• CRITICAL THINKING: A Disease Called Freedom 489
xv
xvi
Contents
FEATURE BOXES (HIGHLIGHTS)
• DISCOVERING PSYCHOLOGY: Feeling a Little Tense?
Relax! 506
PSYCHOLOGY IN ACTION:
Assertiveness Training — Standing Up for Your Rights 551
CHAPTER IN REVIEW 553
• DISCOVERING PSYCHOLOGY: Ten Irrational
Beliefs — Which Do You Hold? 511
WEB RESOURCES 555
• THE CLINICAL FILE: Overcoming the Gambler’s
Fallacy 512
FEATURE BOXES (HIGHLIGHTS)
• CRITICAL THINKING: Touch and Status 532
• CRITICAL THINKING: How Do We Know Therapy
Actually Works? 514
• THE CLINICAL FILE: Self-Handicapping — Smoke
Screen for Failure 534
• HUMAN DIVERSITY: Therapy and Culture — A Bad
Case of “Ifufunyane” 517
• CRITICAL THINKING: Groupthink — Agreement at Any
Cost 543
16 Social Thinking
and Social Influence
• CRITICAL THINKING: How to Drive a Hard
Bargain 546
529
Preview: Six Degrees of Separation 530
Humans in a Social Context — People, People,
Everywhere 530
Roles 530
Group Structure and Cohesion 531
Social Cognition — Behind the Mask 533
Attribution Theory 533
Actor and Observer 534
Attitudes — Belief Emotion Action 535
Forming Attitudes 536
Attitudes and Behavior 536
Attitude Measurement 537
Attitude Change — Why the Seekers Went
Public 537
Persuasion 538
Cognitive Dissonance Theory 538
Social Influence — Follow the Leader 540
Social Power 540
Mere Presence — Just Because You Are
There 541
Social Facilitation and Loafing 541
Personal Space 541
Spatial Norms 542
Conformity — Don’t Stand Out 542
The Asch Experiment 543
Group Factors in Conformity 544
Compliance — A Foot in the Door 544
Passive Compliance 545
Obedience — Would You Electrocute a
Stranger? 547
Milgram’s Obedience Studies 547
Coercion — Brainwashing and Cults 549
Brainwashing 549
Cults 549
INTERACTIVE LEARNING 555
• DISCOVERING PSYCHOLOGY: Quack Like a Duck 548
17 Prosocial and Antisocial
Behavior 556
Preview: Love and Hate 557
The Need for Affiliation — Come Together 557
Social Comparison Theory 557
Interpersonal Attraction — Social Magnetism? 558
Physical Proximity 558
Physical Attractiveness 559
Competence 559
Similarity 559
Self-Disclosure 560
Social Exchange Theory 560
Liking and Loving — Dating, Rating, Mating 561
Love and Attachment 562
Evolution and Mate Selection 562
Helping Others — The Good Samaritan 564
Bystander Intervention 564
Who Will Help Whom? 565
Positive Psychology: Everyday Heroes 566
Aggression — The World’s Most Dangerous
Animal 566
Instincts 567
Biology 567
Frustration 567
Social Learning 568
The World According to TV 568
Preventing Aggression 570
Prejudice — Attitudes That Injure 571
Becoming Prejudiced 572
The Prejudiced Personality 573
Intergroup Conflict — The Roots of Prejudice 573
Experiments in Prejudice 576
PSYCHOLOGY IN ACTION:
Multiculturalism — Living with Diversity 579
Contents
CHAPTER IN REVIEW 581
WEB RESOURCES 582
PSYCHOLOGY IN ACTION:
Human Factors Psychology —Who’s the Boss Here? 607
INTERACTIVE LEARNING 583
CHAPTER IN REVIEW 610
FEATURE BOXES (HIGHLIGHTS)
WEB RESOURCES 611
• CRITICAL THINKING: Pornography and Aggression
Against Women — Is There a Link? 569
INTERACTIVE LEARNING 611
• DISCOVERING PSYCHOLOGY: I’m Not Prejudiced,
Right? 572
• CRITICAL THINKING: From Glass Ceiling to
Labyrinth 587
• HUMAN DIVERSITY: Choking on Stereotypes 574
• THE CLINICAL FILE: Desk Rage and Healthy
Organizations 590
• CRITICAL THINKING: Terrorists, Enemies, and
Infidels 575
• HUMAN DIVERSITY: Is America Purple? 576
FEATURE BOXES (HIGHLIGHTS)
• DISCOVERING PSYCHOLOGY: Surviving Your Job
Interview 591
• CRITICAL THINKING: Territoriality 594
18 Applied Psychology
584
Preview: Insanely Great 585
Industrial/Organizational
Psychology — Psychology at Work 585
Theories of Leadership 585
Theory X and Theory Y Leadership 586
Job Satisfaction 588
Job Enrichment 589
Organizational Culture 589
Personnel Psychology 590
Job Analysis 590
Selection Procedures 590
Environmental Psychology — Life on Spaceship
Earth 593
Environmental Influences 595
Stressful Environments 595
Toxic Environments 597
Sustainable Lifestyles 597
Social Dilemmas 598
Environmental Problem Solving 600
Conclusion 600
Educational Psychology — An Instructive
Topic 601
Elements of a Teaching Strategy 601
Psychology and Law — Judging Juries 602
Jury Behavior 602
Jury Selection 603
Sports Psychology — The Athletic Mind 604
Motor Skills 606
Positive Psychology: Peak Performance 606
• DISCOVERING PSYCHOLOGY: Reuse and
Recycle 599
• HUMAN DIVERSITY: Peanut Butter for the Mind:
Designing Education for Everyone 602
• CRITICAL THINKING: Death-Qualified Juries 604
Appendix: Behavioral Statistics
612
Preview: Statistics from “Heads” to
“Tails” 613
Descriptive Statistics — Psychology by the
Numbers 613
Graphical Statistics 613
Measures of Central Tendency 614
Measures of Variability 615
Standard Scores 616
The Normal Curve 616
Correlation — Rating Relationships 618
Relationships 618
The Correlation Coefficient 618
Inferential Statistics — Significant Numbers 620
Samples and Populations 621
Significant Differences 621
APPENDIX IN REVIEW 622
WEB RESOURCES 622
INTERACTIVE LEARNING 622
Glossary G-1
References R-1
Name Index N-1
Subject Index S-1
xvii
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preface to the twelfth edition
An Invitation to the Student
Greetings from your authors. We are delighted to be your guides as
you explore the exciting field of psychology. We hope you will find
that psychology is at once familiar, exotic, surprising, and challenging. What, really, could be more intriguing than our evolving
understanding of human behavior?
Psychology is about each of us. It invites us to adopt a reflective attitude as we ask, “How can we step outside ourselves to look
objectively at how we live, think, feel, and act?” Psychologists
believe the answer is through intelligent thought, observation,
and inquiry. As simple as that might seem, careful reflection takes
practice to develop. It is the guiding light for all that follows.
Reading Gateways to Mind and Behavior
We trust you will find much that interests you in this book. To
make your reading enjoyable, we tried to write as if we were talking
with you. And to add to your interest, we will often invite you to
relate psychology to your own experiences. But make no mistake,
Gateways to Mind and Behavior is a sophisticated textbook that
offers you an up-to-date introduction to psychology.
At the beginning of each chapter you will find a list of Gateway
Questions to guide your reading. As you read a chapter, try to see
if you can discover the answers to these questions. Then compare
your answers with the ones listed in the chapter summary. The
answers are what we think of as Gateway concepts. In other words,
they open intellectual pathways and summarize psychology’s “big
ideas.” Although you don’t need to memorize the Gateway concepts, you can use them to review the most important points in
each chapter. Ultimately, the Gateway concepts will provide a good
summary of what you learned in this course. If you remember most
of them 10 years after you finish reading this book, you will make
us very happy, indeed.
Studying Gateways to Mind and Behavior
None of us likes to start a new adventure by reading a manual. We
want to get right into a new computer game, step off the airplane
and begin our vacation, or just start using our new camera or cell
phone. You might be similarly tempted to just start reading this
textbook.
Please be patient. Successfully learning psychology depends
on how you study this book, as well as how you read it. Gateways
to Mind and Behavior is your passport to an active adventure in
learning, not just passive reading. To help you get off to a good
start, we strongly encourage you to read our short Introduction,
which precedes Chapter 1. The Introduction describes study skills,
including the SQ4R method, that you can use to get the most out
of this text and your psychology course. It also tells how you can
explore psychology through the Internet, electronic databases, and
interactive CDs.
Each chapter of this book will take you into a different realm of
psychology, such as personality, abnormal behavior, memory, consciousness, and human development. Each realm is complex and
fascinating in its own right. Gateways to Mind and Behavior is your
passport to an adventure in learning. In a very real sense, we wrote
it about you, for you, and to you.
An Invitation to the Instructor
Thank you for choosing this book for your students and your
course. Marcel Proust wrote, “The real voyage of discovery consists not in seeing new landscapes but in having new eyes.” It is
in this spirit that we encourage you to use this book’s special features to help change the way your students see human behavior.
Accordingly, we have written this book to promote an interest in
human behavior, including an appreciation of the practical applications of psychology, the richness of human diversity, and the
field of positive psychology. At the same time, we have structured
this book to help students learn efficiently and apply criticalthinking skills. Without such skills, students cannot easily go, as
Jerome Bruner put it, “beyond the information given” (Bruner,
1973).
To help students read more effectively, we open every chapter
with a list of Gateway Questions that students can use as powerful
advance organizers for digesting new information (e.g., Ausubel,
1978). These questions are addressed throughout the chapter and
are explicitly answered in the chapter summaries. Featured in these
summaries are psychology’s Gateway concepts — the “take home”
ideas every student should remember 10 years after reading this
text. As a whole, they are capable of transforming the way students
view human behavior.
Now widely emulated, earlier editions of Gateways to Mind
and Behavior revolutionized textbooks by using psychology to
help students learn more effectively. We continue that tradition of
innovation in this edition. We have again updated our presentation of the SQ4R method to better promote active learning, longterm retention of ideas, and the reflective attitude that lies at the
heart of critical thinking.
In the previous edition we replaced the “Relate” step of the
SQ4R method with “Reflect,” so that SQ4R now refers to Survey,
Question, Read, Recite, Reflect, and Review. In every chapter, we
have refined the Reflect step of the SQ4R method to strengthen
connections among learning, elaborative processing, and critical
thinking (Gadzella, 1995). For example, we have redesigned the
chapter pedagogy to make it even clearer to students why it is valuable to engage in reflection while reading.
xix
xx
Preface to the Twelfth Edition
Readability and Narrative Emphasis
Selecting a textbook is half the battle in teaching a successful
course. When a book overwhelms students or cools their interest,
teaching and learning suffer. A good text does much of the work
of imparting information to your students. This frees class time for
your discussion, extra topics, or media presentations. It also leaves
students asking for more.
Many introductory psychology students are reluctant readers.
No matter how interesting a text may be, its value is lost if students fail to read it. That’s why we’ve worked hard to make this
a clear, readable, and engaging text. We want students to read
this book with genuine interest and enthusiasm, not merely as
an obligation.
To encourage students to read, we made a special effort to weave
narrative threads through every chapter. Everyone loves a good
story, and the story of psychology is among the most compelling
to be told. Throughout Gateways to Mind and Behavior, we have
used intriguing anecdotes and examples to propel reading and sustain interest. As students explore concepts, they are encouraged to
think about ideas and relate them to current events and their own
experiences.
Practical Applications
Gateways to Mind and Behavior is designed to give students a clear
grasp of major concepts without burying them in details. At the
same time, it offers a broad overview that reflects psychology’s rich
heritage of ideas. We think students will find this book informative and intellectually stimulating. Moreover, we have emphasized
the many ways that psychology relates to practical problems in
daily life.
A major feature of this book is the Psychology in Action section
found at the end of each chapter. These high-interest discussions
bridge the gap between theory and practical application. We believe
it is fair for students to ask, “Does this mean anything to me? Can I
use it? Why should I learn it if I can’t?” The Psychology in Action
features show students how to solve problems and manage their
own behavior. This allows them to see the benefits of adopting new
ideas, and it breathes life into psychology’s concepts.
An Integrated Study Guide
The chapters of this text are divided into short segments by special sections called Knowledge Builders. These “mini study guides”
challenge students to relate concepts to their own experiences, to
quiz themselves, and to think critically about the principles they
are learning. For this edition, we have reorganized the Knowledge
Builders into Recite and Reflect sections, to better mirror the
SQ4R method. Recite questions are somewhat easier than inclass test questions and are designed provide immediate feedback
to students. Reflect questions come in two “flavors.” Critical
Thinking questions encourage critical reflection and come with
answers. Relate questions are open-ended invitations to students
to elaborate on just-read material by relating it to their personal
experiences.
If students would like even more feedback and practice, Chapter
Quizzes are available in a free booklet, Gateways to Mind and
Behavior: Concept Maps and Concept Reviews; a traditional Study
Guide is available; and students can use a web-based course-management tool called WebTutor™ to take online quizzes or to practice with electronic flash cards. Gateways to Mind and Behavior:
Concept Maps and Concept Reviews accompanies every new copy
of the text and also includes Gateway concepts for every chapter,
concept maps of key concepts, and concept reviews (consisting of a
30-item multiple-choice quiz for each chapter). This useful booklet is available to qualified adopters; please consult your local sales
representative for details.
Electronic Resources
To encourage further exploration, students will find a section called
Web Resources at the end of each chapter. The websites described
there offer a wealth of information on topics related to psychology. All chapters include a list of relevant modules in PsychNow!
2.0. This excellent CD-ROM from Wadsworth provides students
with a rich assortment of interactive learning experiences, animations, and simulations.
On the web, students can visit this text’s Book Companion
Website, where they will find quizzes, a final exam, chapter-bychapter web links, flash cards, an audio glossary, and more (www.
cengage.com/psychology/coon).
Students can also make use of CengageNOW for Coon and
Mitterer’s Introduction to Psychology: Gateways to Mind and
Behavior, Twelfth Edition, a web-based, personalized study system that provides a pretest and a posttest for each chapter and
separate chapter quizzes. CengageNOW for Coon and Mitterer’s
Introduction to Psychology, Twelfth Edition, can also create personalized study plans — which include rich media such as videos,
animations, and learning modules — that point students to areas
in the text that will help them master course content. An additional set of integrative questions helps students pull all the material together.
Human Diversity
Today’s students reflect the multicultural, multifaceted nature of
contemporary society. In Gateways to Mind and Behavior, students
will find numerous discussions of human diversity, including differences in race, ethnicity, culture, gender, abilities, sexual orientation,
and age. Too often, such differences needlessly divide people into
opposing groups. Our aim throughout this text is to discourage stereotyping, prejudice, discrimination, and intolerance. We’ve tried
to make this book gender neutral and sensitive to diversity issues.
All pronouns and examples involving females and males are equally
divided by gender. In artwork, photographs, and examples, we have
tried to portray the rich diversity of humanity. In addition, a boxed
feature, Human Diversity, appears throughout the book, providing
students with examples of how to be more reflective about human
diversity. In short, many topics and examples in this book encourage students to appreciate social, physical, and cultural differences
and to accept them as a natural part of being human.
Preface to the Twelfth Edition
Positive Psychology
In January 2000, Martin Seligman and Mihaly Csikszentmihalyi
co-edited a special issue of American Psychologist devoted to optimal functioning, happiness, and “positive psychology.” Over the
past 100 years, psychologists have paid ample attention to the negative side of human behavior. This is easy to understand because
we urgently need to find remedies for human problems. However,
Seligman and Csikszentmihalyi have urged us to also study positive psychology. What do we know, for instance, about love, happiness, creativity, well-being, self-confidence, and achievement?
Throughout this book, we have attempted to answer such questions for students. Our hope is that students who read this book
will gain an appreciation for the potential we all have for optimal
functioning. Also, of course, we hope that they will leave introductory psychology with emotional and intellectual tools they can use
to enhance their lives.
How Chapter Features Support the SQ4R Method
Introduction to Psycholog y was the first college text with an
SQ4R, active-learning format. Through Dennis Coon’s pioneering efforts, this book has made learning psychology a rewarding
experience for more than 2 million students. With their feedback and generous help from many professors, we have continued to refine the unique features of Gateways to Mind and
Behavior.
Notice how the steps of the SQ4R method — survey, question,
read, recite, reflect, and review — are incorporated into the chapter
design.
Survey Features at the beginning of each chapter help students
build cognitive maps of upcoming topics, thus serving as advance
organizers. Students begin with a chapter Theme and a list of
Gateway Questions that identify the main points students should
search for as they read. Next, a short Preview arouses interest, gives
an overview of the chapter, and focuses attention on the task at
hand. These chapter-opening features encourage students to read
with a purpose and actively process information.
Question Throughout each chapter, frequent italicized Guide
Questions also serve as advance organizers. That is, Guide Questions
prompt students to look for important ideas as they read and thus
promote active learning. They also establish a dialogue in which
the questions and reactions of students are anticipated. This clarifies difficult points — in a lively give-and-take between questions
and responses.
Read We’ve made every effort to make this a clear, readable text.
To further aid comprehension, we’ve used a full array of traditional learning aids. These include boldface terms (with phonetic
pronunciations), bullet summaries, a robust illustration program,
summary tables, a name index, a subject index, and a detailed glossary. As an additional aid, figure and table references in the text are
marked with small geometric shapes. These “placeholders” make
it easier for students to return to reading after they have paused to
view a table or figure.
xxi
An Integrated Glossary aids reading comprehension by providing precise definitions directly in context. When important terms
first appear, they are immediately defined. In this way, students
get clear definitions when and where they need them — in the
general text itself. In addition, a parallel Running Glossary defines
key terms in the margins of pages. The Running Glossary makes it
easier for students to find, study, and review important terms.
Recite Every few pages, a Knowledge Builder gives students a
chance to test their recall and understanding of preceding topics.
As mentioned earlier, the Knowledge Builders are small, built-in
study guides that include a Recite section (a short, noncomprehensive quiz), which helps students actively process information
and assess their progress. Recite questions are not as difficult as
in-class tests, and they are just a sample of what students could
be asked about various topics. Students who miss any items are
asked to backtrack and clarify their understanding before reading
more. Completing Recite questions serves as a form of recitation
to enhance learning.
Reflect Cognitive psychology tells us that elaboration, the reflective processing of new information, is one of the best ways to foster understanding and form lasting memories (Anderson, 2005;
Gadzella, 1995; Goldstein, 2008). The more students elaborate
ideas as they read and study, the richer their understanding will be
and the better they will remember new concepts.
Self-reference, a particularly powerful form of elaboration,
makes new information more meaningful by relating it to what is
already known (Klein & Kihlstrom, 1986). Discovering Psychology
boxes in this edition are “try-it” demonstrations that allow students
to observe interesting facets of their own behavior or do self-assessment exercises. In this way, students can link new information to
concrete experiences.
To help students further elaborate their new understanding,
each Knowledge Builder includes a series of Relate questions that
encourage students to associate new concepts with personal experiences and prior knowledge.
A course in psychology also naturally contributes to deeper
forms of reflection, such as the development of critical-thinking
abilities. As we described earlier, to further facilitate reflection, each
Knowledge Builder also includes one or more Critical Thinking
Questions to further facilitate reflection. These stimulating questions challenge students to think critically and analytically about
psychology. Each is followed by a brief answer with which students
can compare their own thoughts. Many of these answers are based
on research and are informative in their own right.
In addition, several boxed highlights encourage other forms of
reflective thought. The Critical Thinking boxes model a reflective
approach to critical thinking in psychology. In addition, Human
Diversity boxes encourage reflection on the variability of human
experience, The Clinical File boxes help students think about clinical applications of psychology, and Brainwaves boxes, which are
new to this edition, encourage reflection on brain mechanisms
that underlie psychological phenomena.
Finally, Bridges appear throughout the text. Each Bridge links
a topic under discussion to related information elsewhere in the
xxii
Preface to the Twelfth Edition
book. This feature helps students reflect on the rich interconnection of ideas in contemporary psychology.
Review As noted previously, all important terms appear in a
Running Glossary throughout the book, which aids review. As also
noted, a Psychology in Action section shows students how psychological concepts relate to practical problems, including problems
in their own lives. The information found in Psychology in Action
helps reinforce learning by illustrating psychology’s practicality.
Next, a point-by-point summary provides a concise synopsis of
all major concepts. The Chapter in Review summary is organized
around answers to the Gateway Questions found at the beginning
of the chapter. This brings the SQ4R process full circle and provides
closure with respect to the learning objectives of each chapter.
Critical Thinking
The active, questioning nature of the SQ4R method is, in itself, an
inducement to think critically. Many of the Guide Questions that
introduce topics in the text act as models of critical thinking. So do
the Critical Thinking, Human Diversity, Discovering Psychology,
The Clinical File, and Brainwaves boxes. Further, Chapter 1 contains a discussion of critical-thinking skills and a rational appraisal
of pseudo-psychologies. In addition, the research methods portion of Chapter 1 is basically a short course on how to think clearly
about behavior. It is augmented by tips about how to critically
evaluate claims in the popular media. Chapter 9, which covers
intelligence, cognition, language, and creativity, includes many
topics related to critical thinking. Taken together, these features
will help students gain thinking skills of lasting value.
Psychology: Gateways to Mind and Behavior —
What’s New?
Thanks to psychology’s vitality, this text is improved in many ways.
Most importantly, the book has been shortened to 18 chapters.
Two developmental psychology chapters have been combined into
one, as have two chapters on intelligence and cognition, language,
and creativity. This major change is based on feedback suggesting that a 20-chapter book presents too much material to cover in
most introductory courses.
This edition also features an updated SQ4R system, outlined
elsewhere in this Preface. The refinements strengthen the link
between remembering new information and thinking reflectively
and critically about psychology.
Finally, the Twelfth Edition of Introduction to Psychology:
Gateways to Mind and Behavior features some of the most recent
and interesting information in psychology. Research references
have been extensively updated, with fully two thirds of citations
dated 2000 or newer. The following annotations highlight some
of the new topics and features that appear in this edition.
Learning Check questions are now Recite questions. A new section
titled Reflect now includes Relate questions and Critical Thinking
questions. This change is designed to make it clearer to students
that relating new information to personal experiences and thinking critically about new ideas are both forms of reflective cognition. In addition, the Introduction shows students how to read
effectively, study more efficiently, take good notes, prepare for
tests, take tests, create study schedules, and avoid procrastination.
Chapter 1: Introduction to Psychology
and Research Methods
•
•
•
•
•
•
•
Chapter 2: Brain and Behavior
•
•
•
•
•
Introduction: The Psychology of Studying
We have once again updated our SQ4R framework. The
Knowledge Builders have been restructured so that students can
more easily see how they relate to the SQ4R method. Specifically,
Chapter 1 has been extensively reorganized and updated and
begins with a more engaging chapter-opening vignette.
Critical thinking is now covered early in the chapter and is
immediately followed by a discussion of the scientific method.
This placement permits students to more tightly link critical
thinking and scientific thought.
The history of psychology is now presented after a discussion
of critical thinking and the scientific method. This arrangement gives students a fuller context for understanding historical changes in psychology.
Modern views on behavior have been reorganized into three
major perspectives: biological, behavioral, and sociocultural.
A new Critical Thinking highlight, “That’s Interesting, but Is
It Ethical?” provides increased coverage of research ethics in
psychology.
The material on placebo effects and the experimenter effect
has been rewritten to include both research participant bias
and experimenter bias. Placebo effects are treated as a form of
research participant bias.
The experimental method is now explored first, before other
research methods. Nonexperimental methods (case studies, surveys, correlations, and natural observation) are then
addressed as alternative research strategies.
•
Chapter 2 has been enlarged to reflect the growing importance
of neuroscience in contemporary psychology. Additional neuroscience content can also be found in subsequent chapters
(most noticeably in the new Brainwaves boxes).
The section on neural transmission now includes information
about myelin and saltatory conduction.
The explanation of neural networks has been expanded and
includes a new explanatory figure.
Artwork illustrating the structure of the nervous system has
been unified for greater simplicity and clarity.
Coverage of the spinal cord, which concludes with an appraisal
of the possibility of spinal cord repair, is now followed by a
Critical Thinking box, “Brain Repair.”
The discussion of neuroscience research methods has been
rewritten to more clearly distinguish ablation from electrical
stimulation.
Preface to the Twelfth Edition
•
•
The lobes of the cerebral cortex are covered in a new order, and
the entire topic has been revised, including an updated figure.
A new Critical Thinking box, “Mirror, Mirror, in the Brain,”
discusses the discovery of mirror neurons and their possible
significance.
Chapter 3: Human Development
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•
•
•
Chapter 3 combines major topics from Child Development
(Chapter 3 of the previous edition) and Human Development
(Chapter 4 of the previous edition). The resulting chapter
moves from infancy through childhood to adulthood.
Material on heredity and environmental influences has been
reorganized and streamlined. Most notably, maturation is now
treated in the heredity section, along with readiness.
The section on the newborn has been reorganized for greater
clarity.
The discussion of Piaget’s theory has also been reorganized.
Transformations are now introduced in a subsection about
the preoperational stage. Simple exercises have been added to
make it easier for students to assimilate the concepts of internal representations and transformations.
Chapter 4: Sensation and Reality
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•
•
•
•
•
•
Chapter 4 begins with a new vignette about echolocation by
bats that illustrates the limits of our senses.
For greater clarity, the first section has been restructured to
combine the previously separated topics of sensory limits and
psychophysics.
A more helpful metaphorical comparison is now drawn
between the visual system and digital cameras.
Material on blindsight is now presented in a Brainwaves box,
“Blindsight: The ‘What’ and the ‘Where’ of Vision,” which
has been expanded to include a new figure illustrating the dorsal and ventral visual pathways.
A new Discovering Psychology box titled “Going Biosonar”
harks back to the chapter-opening vignette about bat echolocation by describing a blind human teenager who echolocates.
Students are given instructions about how to navigate by
echolocation.
The discussion of hearing loss has been revised to follow current terminology (i.e., sensorineural hearing loss and conductive
hearing loss).
The material on gustation and olfaction has been rewritten. In
particular, anosmia is now referred to as dysosmia.
•
•
•
xxiii
Because attention is an early stage of the perceptual process, we
now discuss it earlier in the chapter.
Student feedback suggests that it is easier to understand perceptual organization before tackling perceptual constancies.
Accordingly, Gestalt principles are now covered before perceptual constancies are introduced.
The section on depth perception has also been reorganized
and streamlined. In particular, depth cues are now separated
into binocular and monocular cues. Muscular depth cues have
been omitted as a separate category because the heading mixed
a binocular cue (convergence) with a monocular one (accommodation).
Chapter 6: States of Consciousness
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•
•
•
•
•
•
Chapter 6 features revised coverage of sleep and dreaming.
The dual process hypothesis, which assigns different functions
to NREM and REM sleep, is now discussed.
The treatment of dreaming has been updated to include
Domhoff ’s neurocognitive theory as a complement to psychodynamic and activation-synthesis theories.
The section on hypnosis has also been rewritten for greater
clarity.
Meditation is now treated in a section along with REST
(restricted environmental stimulation therapy), and both are
related to the relaxation response.
A new Brainwaves box, “How Drugs Affect the Brain,” was
fashioned from existing material and includes a new figure.
Statistics have been updated throughout the chapter, such as
those concerning rates of drug abuse and the percentage of
accidents related to sleepiness.
Chapter 7: Conditioning and Learning
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•
•
•
Chapter 7 opens with an engaging new vignette about acquiring a phobia. This example better highlights differences
between associative and cognitive learning, a distinction that is
also more clearly reflected throughout the chapter.
The section on classical conditioning has been streamlined for
greater clarity.
A new Brainwaves box, “Tickling Your Own Fancy,” updates
coverage of the self-stimulation phenomenon.
Are animals aware of the past? A new Critical Thinking box,
“Are Animals Stuck in Time?” explores this interesting question and also shows how operant conditioning can be used as a
research technique.
Chapter 8: Memory
Chapter 5: Perceiving the World
•
•
Chapter 5 has been extensively reorganized to allow students to
draw sharper distinctions between sensation and perception.
The first section in the chapter explains in more detail
why perception is a necessary extra step beyond sensation,
and it includes a discussion of bottom-up and top-down
processing.
•
•
•
The three-store memory model is now clearly labeled as the
Atkinson-Schiffrin model.
The term “dual memory” has been eliminated to avoid confusing students.
The term “elaborative rehearsal” has been changed to “elaborative encoding” to better tie elaboration to encoding, one of the
three fundamental memory processes.
xxiv
•
•
•
•
•
Preface to the Twelfth Edition
A new Critical Thinking box, “Do You Like Jam with Your
Memory?” shows students how advertisers try to manipulate memory. It also serves as an interesting example of
(re)constructive processing.
Discussions of exceptional memory and strategies for improving memory have been extensively reorganized and rewritten.
To help students remember why we forget, theories of forgetting are now organized into three categories: encoding failure,
storage failure, and retrieval failure.
Material on the neuroscience of memory has been reorganized.
In particular, flashbulb memories are now included in a section on memory and emotion and linked to the role the amygdala plays in processing emotional memories.
The section on improving memory has been reorganized
into two subsections that tell students how they can improve
encoding and retrieval.
Chapter 9: Intelligence, Cognition, Language,
and Creativity
•
•
•
•
This chapter is a condensation of Cognition, Language,
and Creativity (Chapter 10 of the previous edition) and
Intelligence (Chapter 11 of the previous edition).
The chapter has also been streamlined for greater interest and
readability.
The distinction between multiple intelligences and intelligence as a g-factor is given more prominence.
The coverage of artificial intelligence has been rewritten and is
now included in the section on intelligence.
•
•
Chapter 12: Personality
•
•
•
•
•
•
•
•
•
Chapter 10 opens with a new vignette featuring an interesting
case study of alexithymia.
The topic of hunger has been restructured into major sections
that discuss internal and external factors affecting eating.
A new Brainwaves box, “Your Brain’s ‘Fat Point,’” discusses setpoints and the role of leptin in hunger and feeding.
The material on eating disorders has been reworked and now
includes information about eating disorders in men.
A new Discovering Psychology box, “Behavioral Dieting,”
more clearly invites students to apply behavioral principles to
control their own eating behavior.
To help students better organize their understanding, the
Psychology in Action section on emotional intelligence has
been reorganized around a revised definition of emotional
intelligence.
Hereditary influences on personality have been moved forward into the first section of this chapter.
A new The Clinical File box, “Telling Stories about Ourselves,”
explores narrative psychology and personality change.
Information about when personality “hardens” has been
rewritten.
Direct and indirect aggression are clearly differentiated in the
discussion of personality and gender.
Chapter 13: Health, Stress, and Coping
•
•
•
•
A new table updates information about the top ten stressors.
Material on the general adaptation syndrome and psychoneuroimmunology now appears at the beginning of this chapter.
A new Discovering Psychology box, “Unhealthy Birds of a
Feather,” presents some new data on the social transmission of
healthy and unhealthy behaviors.
The Critical Thinking box, “It’s All in Your Mind,” has been
rewritten.
Chapter 14: Psychological Disorders
•
Chapter 10: Motivation and Emotion
•
Material on gender development is now presented in a single
section of the chapter.
A new Human Diversity box, “High Test,” discusses how testosterone affects men.
•
•
•
•
•
Chapter 14 has been reorganized for greater clarity.
Specifically, the presentation of disorders has been rearranged.
We now begin with psychotic disorders (to lead with a malady
that is dramatic and highly interesting to students), and follow
with mood disorders, anxiety disorders, and personality disorders. This ordering is easier for students to understand, and it
matches the order of topics provided at the beginning of the
chapter.
A new Brainwaves box, “The Schizophrenic Brain,” better
highlights for students some differences between schizophrenic and normal brains.
The Human Diversity box, “Running Amok with Cultural
Maladies,” has been updated.
A new The Clinical File box, titled “Sick of Being Sick,” introduces students to the fascinating topic of Munchausen syndrome by proxy.
The discussion of insanity now occurs near the front of the
chapter, where it makes better connections with related topics.
The Critical Thinking box, “The Politics of Madness,” has
been repositioned to the end of the chapter.
Chapter 11: Gender and Sexuality
•
•
•
The flow of topics in this chapter has been reorganized.
Information about sexual development has been moved to the
beginning of the chapter, which helps clarify the sequence of
sexual development.
Sexual orientation is discussed earlier in the chapter and is
characterized as an intrinsic biological component of sexual
development.
Chapter 15: Therapies
•
•
•
•
Chapter 15 has received a relatively light update.
The section on cybertherapy has been rewritten and updated.
A new description of interpersonal psychotherapy (IPT) has
been added.
The coverage of somatic therapies includes a discussion of
electrical stimulation of the brain (other than ECT).
Preface to the Twelfth Edition
•
A new The Clinical File box, “Overcoming the Gambler’s
Fallacy,” introduces students to the problem of compulsive
gambling and relates it to cognitive therapies.
xxv
The Psychology in Action section has been rewritten to introduce students to human factors, with a focus on the study of
human–computer interaction.
Chapter 16: Social Thinking and Social Influence
•
•
•
•
•
•
The two social psychology chapters (Chapters 16 and 17)
have been extensively reorganized. Chapter titles have changed
accordingly.
Attribution (from the previous Chapter 16), attitudes, and
attitude change (from the old Chapter 17) are discussed
together, as forms of social thinking.
The remaining topics from the former Chapter 16 now appear
as an extended discussion of social influence, presented in
order from mild to strong forms of influence.
The effect of mere presence is now discussed, as are social
facilitation and social loafing. Invasions of personal space are
reinterpreted as a form of mere presence.
The presentation of social influence then moves from conformity to compliance and obedience.
Coercion, which is the final topic in this series, is composed
mainly of material on brainwashing and cults from the old
Chapter 17.
Chapter 17: Prosocial and Antisocial Behavior
•
•
•
•
•
As the new chapter title implies, Chapter 17 now focuses on
prosocial and antisocial behavior.
The presentation of prosocial behavior has been broadened to
include affiliation, liking, and loving, as well as a willingness to
help strangers.
An exploration of affiliation, liking, and loving now opens this
chapter.
Robert Sternberg’s triangular theory of love is now included
because it is highly interesting to students.
A new Human Diversity box, “Purple America,” invites students to think beyond stereotyping American citizens as either
“red” or “blue” (Republican or Democrat).
Chapter 18: Applied Psychology
•
•
•
•
•
•
The chapter-opening vignette now discusses how human factors have contributed to the iPod’s success, a topic of great
interest to students.
The section on industrial/organizational psychology has been
rewritten and restructured and now begins with the topic of
leadership.
A new Critical Thinking box, “From Glass Ceiling to
Labyrinth,” describes the challenges women face as business
leaders.
Material on flextime now includes a discussion of compressed
workweeks and telecommuting.
A new Discovering Psychology box, “Surviving Your Job
Interview,” offers concrete advice to students as they look
for jobs.
The discussion of environmental psychology has been revised
and updated to include information about carbon footprints.
A Complete Course — Teaching
and Learning Supplements
A rich array of supplements accompanies Introduction to Psychology:
Gateways to Mind and Behavior, including several that make use of
the latest technologies. These supplements are designed to make
teaching and learning more effective. Many are available free to
professors or students. Others can be packaged with this text at a
discount.
Student Support Materials
Introductory students must learn a multitude of abstract concepts,
which can make a first course in psychology difficult. The materials listed here will greatly improve students’ chances for success.
Gateways to Psychology: Concept Maps and Concept Reviews Concept
Maps created by Christine M. Vanchella and quiz items updated
by Shawn Talbot, Kellogg Community College. For each chapter
of the text, this booklet includes the Gateway concepts, a concept
map, and a 35-item multiple-choice practice exam (ISBN: 0-49582929-3).
Study Guide The Study Guide, written by Thuy Karafa of Ferris State
University and Dennis Coon, is an invaluable student resource. It
contains a variety of study tools, including: Chapter Overviews,
Recite and Review (fill-in-the-blank), Connections (matching),
Check Your Memory (true/false), Final Survey and Review (fill-inthe-blank), and Mastery Test (ISBN: 0-495-80429-0).
Careers in Psychology: Opportunities in a Changing World, Second
Edition This informative booklet, written by Tara L. Kuther, is a
Wadsworth exclusive. The pamphlet describes the field of psychology, as well as how to prepare for a career in psychology. Career
options and resources are also discussed. Careers in Psychology can
be packaged with this text at no additional cost to students (ISBN:
0-495-09078-6).
Multimedia CD-ROMs
Interactive CD-ROMs make it possible for students to directly
experience some of the phenomena they are studying. The following CDs from Wadsworth provide a wealth of engaging modules
and exercises.
PsychNow!™ Interactive Experiences in Psychology 2.0 This exciting CD-ROM was created by Joel Morgovsky, Lonnie Yandell,
Elizabeth Lynch, and project consultant Dennis Coon. At the end
of each chapter of this text, students will find a list of PsychNow!
modules they can access for additional, “hands-on” learning.
PsychNow! provides stunning graphics and animations, interesting
video clips, interactive exercises, and web links, bringing psychology to life. With PsychNow!, students can do more than just read
xxvi
Preface to the Twelfth Edition
about a topic — they can read, watch, listen, react, and reflect on
the meaning of their own responses. PsychNow!, which is available for Macintosh and Windows, contains 39 fully interactive
modules that will enhance their understanding, 8 “Interact Now”
Collaborative Labs, and “Quiz Game Now” quizzes. Students can
also conduct 15 different “Interactive Research Experiments” in
areas such as neurocognition, perception, memory, concepts, and
imagery. PsychNow! 2.0 can be packaged with this text for a discount; contact your sales representative for details (ISBN: 0-53459046-2).
Sniffy™ the Virtual Rat, Lite Version 2.0 There’s no better way to master
the basic principles of learning than working with a real laboratory
rat. However, this is usually impractical in introductory psychology courses. Sniffy the Virtual Rat offers a fun, interactive alternative to working with lab animals. This innovative and entertaining
software teaches students about operant and classical conditioning
by allowing them to condition a virtual rat. Users begin by training
Sniffy to press a bar to obtain food. Then they progress to studying the effects of reinforcement schedules and simple classical conditioning. In addition, special “Mind Windows” enable students
to visualize how Sniffy’s experiences in the Skinner Box produce
learning. The Sniffy CD-ROM includes a Lab Manual that shows
students how to set up various operant and classical conditioning
experiments. Sniffy™ the Virtual Rat, Lite Version 2.0 may be packaged with this text for a discount (ISBN: 0-534-63357-9).
Online Resources
The Internet is providing new ways to exchange information and
enhance education. In psychology, Wadsworth is at the forefront
in making use of this exciting technology.
Book Companion Website As users of this text, you and your students
will have access to the Book Companion Website for Introduction
to Psychology at www.cengage.com/psychology/coon. Access is
free and no pin is required. This outstanding site features chapterby-chapter online tutorial quizzes, a final exam, chapter-by-chapter web links, flash cards, and more!
Th is web -ba se d study a id , by
Christopher B. Mayhorn, North Carolina State University, helps
your students discover the areas of text where they need to focus
their efforts through a series of diagnostic pretests and posttests,
personalized study plans — which include rich media such as videos, animations, and learning modules — that parallel the modules
in the book, eBook files, and other integrated media elements. New
to this edition, students have access to the Psychology Resource
Center included with CengageNow. The new Psychology Resource
Center features powerful teaching and learning tools, bringing
psychology to life with a full library of original and classic video
clips plus interactive learning modules tied to all the topics covered in an introductory psychology course. Organized by topic,
the Psychology Resource Center is easy to navigate by students to
find learning resources, and instructors will also find it an amazing
lecture resource to easily stream multimedia into their classrooms
(ISBN: 0-495-80682-X).
WebTutor This online supplement helps students succeed by taking them into an environment rich with study and mastery tools,
communication aids, and additional course content. For students,
WebTutor offers real-time access to a full array of study tools,
including videos, animations, flash cards (with audio), practice
quizzes and tests, online tutorials, exercises, asynchronous discussion, a whiteboard, and an integrated e-mail system. Students
will also have integrated access to the Newbury House Online
Dictionary, an interactive dictionary that gives users instant access
to definitions (including audio pronunciations).
Professors can use WebTutor to offer virtual office hours, post
syllabi, set up threaded discussions, track student progress on quizzes, and more. You can customize the content of WebTutor in any
way you choose, including uploading images and other resources,
adding web links, and creating course-specific practice materials (WebTutor on WebCT, ISBN: 0-495-80690-0; WebTutor on
Blackboard, ISBN: 0-495-80691-9).
Essential Teaching Resources
As every professor knows, teaching an introductory psychology
course is a tremendous amount of work. The supplements listed
here should not only make life easier for you, they should also
make it possible for you to concentrate on the more creative and
rewarding facets of teaching.
Instructor’s Resource Manual The Instructor’s Resource Manual, by
Wanda McCarthy, Clermont College, University of Cincinnati,
contains resources designed to streamline and maximize the effectiveness of your course preparation. In a three-ring binder format,
this IRM is a treasure trove — from the introduction section, which
includes a Resource Integration Guide, to a full array of chapter
resources. Each chapter includes learning objectives, discussion
questions, lecture enhancements, role-playing scenarios, “oneminute motivators,” broadening-our-cultural-horizons exercises,
journal questions, suggestions for further reading, media suggestions, and web links (ISBN: 0-495-60314-7).
Test Bank The Test Bank was prepared by Jeannette Murphey of
Meridian Community College. It includes over 4,500 multiplechoice questions organized by chapter and by learning objectives. All
items, which are classified as factual, conceptual, or applied, include
correct answers and page references from the text. All questions new
to this edition are identified by an asterisk (ISBN: 0-495-59916-6).
PowerLecture with JoinIn and ExamView This one-stop digital
library and presentation tool includes preassembled Microsoft®
PowerPoint® lecture slides by Andrew Getzfeld, New York
University. In addition to a full Instructor’s Manual and Test
Bank, PowerLecture® also includes all videos from Wadsworth’s
Psychology Digital Video Library 3.0, which can be easily integrated into PowerPoint® for more interactive presentations.
PowerLecture® brings together all your media resources in one
place, including an image library with graphics from the book itself,
video clips, and more. PowerLecture® also includes ExamView®
testing software with all the test items from the printed Test Bank
in electronic format, enabling you to create customized tests in
Preface to the Twelfth Edition
print or online, as well as JoinIn™ Student Response System, offering instant assessment and better student results (ISBN: 0-49580676-5).
Videotapes and Films
Wadsworth offers a variety of videotapes and films to enhance
classroom presentations. Many video segments in the Wadsworth
collection pertain directly to major topics in this text, making
them excellent lecture supplements.
ABC Video for Introductory Psychology, Volume 1 and 2 Available
to adopters, these ABC videos feature short, high-interest clips
about current studies and research in psychology. These videos are perfect to start discussions or to enrich lectures. Topics
include brain damage, measuring IQ, sleep patterns, obsessivecompulsive disorder, obedience to authority, rules of attraction
and much more (Volume 1 ISBN: 0-495-50306-1; Volume 2
ISBN: 0-495-59637-X).
Wadsworth Film and Video Library for Introductory Psychology
Adopters can select from a variety of continually updated film and
video options. The Wadsworth Film and Video Library includes
selections from the Discovering Psychology series, the Annenberg
series, and Films for Humanities. Contact your local sales representative or Wadsworth Marketing at 1-877-999-2350 for details.
Psychology Digital Video Library Version 3.0 CD-ROM This CD-ROM
contains a diverse selection of classic and contemporary clips,
including “Little Albert,” the “Action Potential of a Neuron,”
“Parts of the Brain,” and many more! The digital library offers a
convenient way to access an appropriate clip for every lecture. An
accompanying Digital Video Handbook offers a detailed description, approximate running time, and references to related media
clips. It also offers objective quizzing and critical-thinking questions for each clip, as well as instructions on how to embed clips
into your PowerPoint presentations. Available exclusively to
instructors who adopt Wadsworth psychology texts (ISBN: 0495-09063-8).
Wadsworth Media Guide for Introductory Psychology This essential
instructor resource, edited by Russell J. Watson, contains hundreds
of video and feature film recommendations for all major topics in
introductory psychology (ISBN: 0-534-17585-6).
Supplementary Books
No text can cover all the topics that might be included in an introductory psychology course. If you would like to enrich your course,
or make it more challenging, the Wadsworth titles listed here may
be of interest.
Challenging Your Preconceptions: Thinking Critically about Psychology,
Second Edition This paperbound book (ISBN: 0-534-267394), written by Randolph Smith, helps students strengthen their
critical-thinking skills. Psychological issues such as hypnosis and
repressed memory, statistical seduction, the validity of pop psy-
xxvii
chology, and other topics arc used to illustrate the principles of
critical thinking.
Writing Papers in Psychology: A Student Guide The Sixth Edition of
Writing Papers in Psychology (ISBN: 0-534-52395-1), by Ralph L.
Rosnow and Mimi Rosnow, is a valuable “how to” manual for writing term papers and research reports. This new edition has been
updated to reflect the latest APA guidelines. The book covers
each task with examples, hints, and two complete writing samples.
Citation ethics, how to locate information, and new research technologies are also covered.
Cross-Cultural Perspectives in Psychology How well do the concepts
of psychology apply to various cultures? What can we learn about
human behavior from cultures different from our own? These
questions lie behind a collection of original articles written by
William F. Price and Rich Crapo. The Fourth Edition of CrossCultural Perspectives in Psychology (ISBN: 0-534-54653-6) contains articles on North American ethnic groups as well as cultures
from around the world.
Summary
We sincerely hope that both teachers and students will consider
this book and its supporting materials a refreshing change from
the ordinary. Creating them has been quite an adventure. In the
pages that follow, we believe students will find an attractive blend
of the theoretical and the practical, plus many of the most exciting
ideas in psychology. Most of all, we hope that students using this
book will discover that reading a college textbook can be entertaining and enjoyable.
Acknowledgments
Psychology is a cooperative effort requiring the talents and energies of a large community of scholars, teachers, researchers, and
students. Like most endeavors in psychology, this book reflects the
efforts of many people. We deeply appreciate the contributions of
the following professors who have, over the years, supported this
text’s evolution:
Faren R. Akins
University of Arizona
Nancy L. Ashton
R. Stockton College of New Jersey
Avis Donna Alexander
John Tyler Community College
Scott A. Bailey
Texas Lutheran University
Clark E. Alexander
Arapahoe Community College
Frank Barbehenn
Bucks County Community College
Tricia Alexander
Long Beach City College
Michael Bardo
University of Kentucky
Dennis Anderson
Butler Community College
Larry W. Barron
Grand Canyon University
Lynn Anderson
Wayne State University
Linda M. Bastone
Purchase College, SUNY
xxviii
Preface to the Twelfth Edition
Brian R. Bate
Cuyahoga Community College
Daniel B. Cruse
University of Miami
Hugh E. Bateman
Jones Junior College
Betty J. Daughenbaugh
Wor-Wic Community College
Evelyn Blanch-Payne
Oakwood College
Keith E. Davis
University of South Carolina–
Columbia
Cheryl Bluestone
Queensborough Community
College–CUNY
Diane DeArmond
University of Missouri, Kansas City
Galen V. Bodenhausen
Michigan State University
Patrick T. DeBoll
St. John’s University
Aaron U. Bolin
Arkansas State University
Dawn Delaney
University of Wisconsin–
Whitewater
Tom Bond
Thomas Nelson Community College
John Boswell
University of Missouri, St. Louis
Anne Bright
Jackson State Community College
Soheila T. Brouk
Gateway Technical College
Derek Cadman
El Camino Community College
James F. Calhoun
University of Georgia
Jane Marie Cirillo
Houston Community CollegeSoutheast
Dennis Cogan
Texas Tech University
Lorry Cology
Owens College
Jack Demick
Suffolk University
Lorraine P. Dieudonne
Foothill College
H. Mitzi Doane
University of Minnesota–Duluth
Wendy Domjan
University of Texas at Austin
Roger A. Drake
Western State College of Colorado
John Dworetzky
Glendale Community College
Bill Dwyer
Memphis State University
Thomas Eckle
Modesto Community College
David Edwards
Iowa State University
Darlene Colson
Norfolk State University
Raymond Elish
Cuyahoga Community College
William N. Colson
Norfolk State College
Diane Feibel
University of Cincinnati–Raymond
Walters College
Chris Cozby
California State University, Fullerton
Corinne Crandell
Broome County Community
College
Thomas L. Crandell
Broome County Community
College
Charles Croll
Broome Community College
Paul W. Fenton
University of Wisconsin, Stout
Dave Filak
Joliet Junior College
Gloria Fisher, Ph.D.
Mississippi College
Oney D. Fitzpatrick, Jr.
Lamar University
Linda E. Flickinger
Saint Clair County Community
College
Callina Henson
Oakland Community College–
Auburn Hills
William F. Ford
Bucks County Community College
Anne Hester
Pennsylvania State University–
Hazleton Campus
Marie Fox
Metropolitan State College of
Denver
Gregory P. Hickman
The Pennsylvania State University–
Fayette
Chris Fraser
Gippsland Institute of Advanced
Education
Don Hockenbury
Tulsa Junior College
Christopher Frost
Southwest Texas State University
Sidney Hockman
Nassau Community College
Eugenio J. Galindro
El Paso Community College
Barbara Honhart
Lansing Community College
Irby J. Gaudet
University of Southwestern
Louisiana
John C. Johanson
Winona State University
David Gersh
Houston Community College
David A. Gershaw
Arizona Western College
Andrew R. Getzfeld
New Jersey City University
Carolyn A. Gingrich
South Dakota State University
Perilou Goddard
Northern Kentucky University
Michael E. Gorman
Michigan Technological University
Peter Gram
Pensacola Junior College
David A. Gries
State University of New York,
Farmingdale
R.J. Grisham
Indian River Community College
John Grivas
Monash University
Anne Groves
Montgomery College
Michael B. Guyer
John Carroll University
Janice Hartgrove-Freile
North Harris College
Raquel Henry
Kingwood College
James A. Johnson
Sam Houston State University
Myles E. Johnson
Normandale Community College
Pat Jones
Brevard Community College
Richard Kandus
Menifee Valley Campus
Bruno M. Kappes
University of Alaska–Anchorage
Charles Karis
Northeastern University
John P. Keating
University of Washington
Patricia Kemerer
Ivy Tech Community College
Cindy Kennedy
Sinclair Community College
Shaila Khan
Tougaloo College
Richard R. Klene
University of Cincinnati
Ronald J. Kopcho
Mercer Community College
Mary Kulish
Thomas Nelson Community College
Billie Laney
Central Texas College
Preface to the Twelfth Edition
xxix
Phil Lau
DeAnza College
Beth Moore
Madisonville Community College
Steven J. Pollock
Moorpark College
Glenda Smith
North Harris Community College
Robert Lawyer
Delgado Community College
Feleccia R. Moore-Davis
Houston Community College
System
Jack Powell
University of Hartford
Steven M. Smith
Texas A&M University
Ravi Prasad
Texas Tech University
Francine Smolucha
Moraine Valley Community College
Derrick L. Proctor
Andrews University
Michael C. Sosulski
College of DuPage
Douglas Pruitt
West Kentucky Community College
Lynn M. Sprott
Jefferson Community College
Robin Raygor
Anoka-Ramsey Community College
Donald M. Stanley
North Harris County College
Richard Rees
Glendale Community College
Julie E. Stokes
California State University–
Fullerton
Walter Leach
College of San Mateo
Christopher Legrow
Marshall University
Lindette I. Lent
Arizona Western College
Elizabeth Levin
Laurentian University
Julie Lewis
Georgian College
Elise B. Lindenmuth
York College of Pennsylvania
Linda Lockwood
Metropolitan State College of
Denver
Philip Lom
West Connecticut State University
Cheryl S. Lynch
University of Louisiana–Lafayette
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Owensboro Community College
Edward Mosley
Pasiac County Community College
James Murray
San Jacinto University
Gary Nallan
University of North Carolina–
Ashville
Andrew Neher
Cabrillo College
Don Nelson
Indiana State University
Steve Nida
Franklin University
Peggy Norwood
Tidewater Community College
James P. B. O’Brien
Tidewater Community College
Salvador Macias, III
University of South Carolina,
Sumter
Frances O’Keefe
Tidewater Community College
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Rogers State University
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Central Arizona College
Al Mayer
Portland Community College
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Tarrant County College
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Cape Fear Community College
Darlene Pacheco
Moorpark College
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El Camino College
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College of New Rochelle
Yancy B. McDougal
University of South Carolina,
Spartanburg
Debra Parish
Tomball College
Paul A. Rhoads
Williams College
Harvey Richman
Columbus State University
Marcia Rossi
Tuskegee University
Kim Royster
Tidewater Community College
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Mulhenberg College
James J. Ryan
University of Wisconsin, La Crosse
John D. Sanders
Butler County Community College
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Kirkwood Community College
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Fresno City College
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Spelman College
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Southwest Missouri State University
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University of Cincinnati
Harvey Taub
Staten Island Community College
Christopher Taylor
University of Arizona
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University of Oklahoma
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New Mexico State University
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Miami-Dade Community College–
Kendall Campus
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Santa Barbara City College
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Northeast Iowa Community College
Pat Tuntland
Pima College
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David Lipscomb University
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Texas A&M University
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University of Southwestern
Louisiana
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Rutgers University
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Mercer County Community College
Leon Peek
North Texas State University
Richard Siegel
University of Massachusetts, Lowell
Mark McKinley
Lorain County Community College
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Adirondack Community College
Nancy Simpson
Trident Technical College
Charles Verschoor
Miami-Dade Community College–
Kendall Campus
Chelley Merrill
Tidewater Community College
Peter Phipps
Sullivan County Community
College
Madhu Singh
Tougaloo College
Frank Vitro
Texas Women’s University
A.D. VanDeventer
Thomas Nelson Community College
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Palomar College
xxx
Preface to the Twelfth Edition
John Vojtisek
Castleton State College
Paul J. Wellman
Texas A&M University
Carl D. Williams
University of Miami
Michael Zeller
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Francis Volking
Saint Leo University
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University of Kentucky
Don Windham
Roane State Community College
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Virginia Wesleyan College
Margaret L. Walker
Georgia State University
Robert Wiley
Montgomery College
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College
Otto Zinser
East Tennessee State College
David W. Ward
Arkansas Tech University
Thomas Wilke
University of Wisconsin, Parkside
Producing Introduction to Psychology: Gateways to Mind and
Behavior and its supplements was a formidable task. We are
especially indebted to each of the following individuals for supporting this book: At Cengage Learning, Susan Badger, Sean
Wakely, Eve Howard, Vicki Knight, and Michele Sordi. We are
also grateful to Jaime Perkins for his insight and support. Jaime
has unmistakably contributed to this book. At home, Heather
Mitterer, Kayleigh Hagerman, and Barbara Kushmier helped in
oh so many ways.
We also wish to thank the individuals at Cengage Learning
who have so generously shared their knowledge and talents over
the past year. These are the people who made it happen: Jeremy
Judson, Vernon Boes, Pat Waldo, Rachel Guzman, Ileana Shevlin,
and Kim Russell.
It has been a pleasure to work with such a gifted group of professionals and many others at Cengage Learning. We especially
want to thank Jeremy Judson. As our developmental editor, Jeremy
has gracefully kept us on track and offered many deeply appreciated suggestions.
Dennis Coon
John O. Mitterer
INTRODUCTION
The Psychology of Studying
Eric Audras/PhotoAlto/Jupiterimages
Well Hello There!
You’re actually reading this! As your authors, we’re impressed. Too often, students just jump
in and read a textbook from the first assigned chapter to the last. That’s a shame because
a textbook needs to be studied, not just read. Think about it: How much do you typically
remember after you’ve read straight through a whole textbook chapter? If the answer is
“Nada,” “Zilch,” or simply “Not enough,” it may be because reading a chapter is not really
the same as studying it. Even if you’re an excellent student, you may be able to improve
your study skills. Students who get good grades tend to work smarter, not just longer or
harder (Santrock & Halonen, 2007). To help you get a good start, let’s look at several ways
to improve studying.
1
INTRODUCTION
© 1996 William Haefeli from cartoonbank.com. All Rights Reserved.
2
The SQ4R Method —
How to Tame a Textbook
looking at topic headings, figure captions, and summaries.
Try to get an overall picture of what lies ahead. Because this
book is organized into short sections, you can survey just
one section at a time if you prefer.
Q Question. As you read, turn each topic heading into one
or more questions. For example, when you read the heading “Stages of Sleep” you might ask, “Is there more than one
stage of sleep?” “What are the stages of sleep?” “How do
they differ?” Asking questions helps you read with a purpose.
R1 Read. The first R in SQ4R stands for read. As you read,
look for answers to the questions you asked. Read in short
“bites,” from one topic heading to the next, then stop. For
difficult material you may want to read only a paragraph or
two at a time.
R2 Recite. After reading a small amount, you should pause
and recite or rehearse. Try to mentally answer your questions. Better yet, summarize what you just read in brief
notes. Making notes will show you what you know and
don’t know, so you can fill gaps in your knowledge (Peverly
et al., 2003).
If you can’t summarize the main ideas, skim over each section
again. Until you can remember what you just read, there’s little
point to reading more. After you’ve studied a short “bite” of text,
turn the next topic heading into questions. Then read to the following heading. Remember to look for answers as you read and
to recite or take notes before moving on. Ask yourself repeatedly,
“What is the main idea here?”
Repeat the question–read–recite cycle until you’ve finished an
entire chapter (or just from one Knowledge Builder to the next, if
you want to read shorter units).
What’s the difference between reading a textbook and studying it?
You have probably occasionally spent an evening just vegging out
in front of a TV set. According to psychologist Donald Norman
(1993), you were engaging in experiential cognition. This type of
thinking occurs when you passively let an experience happen to
you. There is nothing wrong with merely experiencing entertainment. But have you noticed that the next morning you often have
trouble remembering what you watched the night before?
In contrast, suppose one of the programs was about, say, global
R3 Reflect. As you read, try to reflect on what you are reading.
warming, and it really got you thinking. You might have wondered
One powerful way to do this is to relate new facts, terms, and
how global warming will affect your own future plans. You might
concepts to information you already know well or to your
have questioned some of the program’s more dire projections for
own experiences. You’ve probably noticed that it is especially
the future. You might have thought back to another program on
easy to remember ideas that are personally meaningful, so
global warming and remembered some different perspectives.
try to relate the ideas you encountered to your own life. This
Now you are “going beyond the information given” (Bruner,
may be the most important step in the SQ4R method. The
1973). For Norman (1993), this is reflective cognition: Rather than
more genuine interest you can bring to your reading, the
just experiencing something, you also actively think about what
more you will learn (Hartlep & Forsyth, 2000).
you experienced. The next morning, you may forget most of what
R4 Review. When you’re done reading, skim back over a secyou watched the night before, but the odds are you will remember
tion or the entire chapter, or read your notes. Then check
the program on global warming. Thus, studying a textbook ideally
your memory by reciting and quizzing yourself again. Try to
involves not just experiencing it, but also actively reflecting on
make frequent, active review a standard part of your study
what you read.
habits ( Figure I.1).
One way to be more reflective while
reading a textbook is to use the SQ4R
method. SQ4R stands for survey, question,
Question
Question
Question
Question
read, recite, reflect, and review. These six
Read
Read
Read
Read
Survey
Review
steps can help you learn as you read and
Recite
Recite
Recite
Recite
Reflect
Reflect
Reflect
Reflect
reflect, remember more, and review effectively:
•
S Survey. Skim through a chapter
before you begin reading it. Start by
Figure I.1 The SQ4R method promotes active learning and information processing. You should begin with a
•survey
of the chapter or section, depending on how much you plan to read. Then you should proceed through cycles
of questioning, reading, reciting, and reflecting, and conclude with a review of the section or the entire chapter.
The Psychology of Studying
Does this really work? Yes. Using a reflective reading strategy
improves learning and course grades (Taraban, Rynearson, &
Kerr, 2000). Simply reading straight through a chapter can give
you “intellectual indigestion.” That’s why it’s better to stop often
to think, question, recite, reflect, review, and “digest” information
as you read.
How to Use Introduction to Psychology: Gateways
to Mind and Behavior
You can apply the SQ4R method to any text. However, we have
specifically designed this textbook to help you actively learn
psychology.
Survey
Each chapter opens with a chapter survey that includes a Gateway Theme and a list of Gateway Questions as well as a Preview
of what will be covered. You can use these features to identify
important ideas as you begin reading. The Preview should help
you get interested in the topics you will be reading about. The
Gateway Theme and Gateway Questions are a good guide to the
kinds of information to look for as you read. In fact, answers to
the Gateway Questions are a good summary of the core concepts
in each chapter. If, years from now, you still remember those
Gateway concepts, your authors will be very happy indeed.
Anyway, after you’ve studied the Gateway Questions, take a few
minutes to do your own survey of the chapter. You should notice
that each major chapter heading is accompanied by one of the
Gateway Questions. This will help you build a “mental map” of
upcoming topics.
Question
How can I use the SQ4R method to make reading more interesting and effective? One of the key steps is to ask yourself a lot of
questions while you read. Dialogue Questions like the one that
began this paragraph will help you focus on seeking information
as you read. These questions are very much like those running
through the minds of students like you as they read this book.
Try to anticipate these questions. Even better, be sure to ask your
own questions. Try to actively interact with your textbooks as
you read.
Read
As an aid to reading, important terms are printed in boldface
type and defined where they first appear. (Some are followed
by pronunciations — capital letters show which syllables are
accented.) You’ll also find a running glossary in the lower righthand corner of pages you are reading, so you never have to guess
about the meaning of technical terms. If you want to look up
a term from a lecture or another chapter, check the main
Glossary. This “mini-dictionary” is located near the end of the
book. Perhaps you should take a moment to find it now. In
addition, many figures and tables help you quickly grasp important concepts.
3
Recite and Reflect
To help you study in smaller “bites,” this book is divided into short
sections that end with Knowledge Builders, which make good stopping points. Knowledge Builders provide opportunities to check
your memory for what you just read. They also invite you to think
more deeply by presenting critical thinking questions and questions designed to help you relate material to your own life. (Don’t
forget to also take notes or recite and reflect on your own.)
This book also provides other opportunities for you to reflect
more deeply about what you are reading. Each chapter ends with
a Psychology in Action section. These discussions are filled with
practical ideas you can relate to your own life. In many chapters,
Discovering Psychology boxes also invite you to relate psychology
to your own behavior. Critical Thinking boxes present intriguing
questions you can use to sharpen your critical thinking skills. In
addition, Human Diversity boxes encourage you to reflect on the
rich variety of human experience; Brainwaves boxes show how the
brain relates to psychology; and in The Clinical File boxes we will
see how psychology can be applied to treat clinical problems.
Review
Each chapter concludes with a detailed review. There you will find
a list of Gateways to psychology. These are summaries of psychology’s “big ideas” and enduring principles. The first time you finish
a chapter, don’t feel obligated to memorize the Gateways concepts.
However, be sure to take a moment to think about each statement.
Ultimately, the Gateways will provide a good high-level summary
of what you learned in this course. By making these ideas your
own, you will gain something of lasting value: You will learn to
see human behavior as psychologists do. Following each Gateways
concept, you will find a more detailed, point-by-point summary of
ideas presented in the chapter. These points will help you identify
important ideas to remember.
For further review, you can use the running glossary in the margin, as well as boldface terms, figures, and tables. Table I.1 summarizes how this text helps you apply the SQ4R method. Even with
all this help, there is still much more you can do on your own.
•
Effective Note-Taking —
Good Students, Take Note!
Reading strategies may be good for studying, but what about taking
notes in class? Sometimes it’s hard to know what’s important. Just as
studying a textbook is best done reflectively, so too is attending class
(Norman, 1993). Like effective reading, good notes come from
actively seeking information. People who are active listeners avoid
distractions and skillfully gather ideas. Here’s a listening/note-taking
SQ4R method An active study-reading technique based on these steps:
survey, question, read, recite, reflect, and review.
Active listener A person who knows how to maintain attention, avoid
distractions, and actively gather information from lectures.
4
INTRODUCTION
Table I.1
• Using the SQ4R Method
Survey
• Preview
• Gateway Theme
• Gateway Questions
• Chapter Preview
• Topic Headings
• Figure Captions
Question
• Topic Headings
• In-Text Dialogue Questions
Read
• Topic Headings
• Boldface Terms
• Running Glossary
• Figures and Tables
Recite
• Recite Questions (in Knowledge Builders)
• Practice Quizzes (online)
• Notes (make them while reading)
Reflect
• Critical Thinking Questions (in Knowledge Builders)
• Relate Questions (in Knowledge Builders)
• Psychology in Action Sections (throughout the text)
• Boxed Highlights (throughout the text)
Review
• Italicized Gateways Concepts
• Boldface Terms
• Running Glossary
• Figure and Tables
• Practice Quizzes (online)
• Study Guide
plan that works for many students. The letters LISAN, pronounced
like the word listen, will help you remember the steps:
L Lead. Don’t follow. Read assigned materials before coming to class. Try to anticipate what your teacher will say by
asking yourself questions. If your teacher provides course
notes or PowerPoint overheads before lectures, review them
before coming to class. Reflective questions can come from
those materials or from study guides, reading assignments,
or your own curiosity.
I Ideas. Every lecture is based on a core of ideas. Usually, an
idea is followed by examples or explanations. Ask yourself
often, “What is the main idea now? What ideas support it?”
S Signal words. Listen for words that tell you what direction the instructor is taking. For instance, here are some
signal words:
There are three reasons why . . .
Here come ideas
Most important is . . .
Main idea
On the contrary . . .
Opposite idea
As an example . . .
Support for main idea
Therefore . . .
Conclusion
A Actively listen. Sit where you can get involved and ask
questions. Bring questions you want answered from the last
lecture or from your text. Raise your hand at the beginning
of class or approach your professor before the lecture. Do
anything that helps you stay active, alert, and engaged.
N Note taking. Students who take accurate lecture notes tend
to do well on tests (Williams & Eggert, 2002). However,
don’t try to be a tape recorder. Listen to everything, but be
selective and write down only key points. If you are too busy
writing, you may not grasp what your professor is saying.
When you’re taking notes, it might help to think of yourself
as a reporter who is trying to get a good story (Ryan, 2001).
Actually, most students take reasonably good notes — and then
don’t use them! Many students wait until just before exams to
review. By then, their notes have lost much of their meaning. If
you don’t want your notes to seem like “chicken scratches,” it pays
to review them every day (Rowe, 2007).
Using and Reviewing Your Notes
When you review, you will learn more if you take the extra
steps listed here (Knaus & Ellis, 2002; Rowe, 2007; Santrock &
Halonen, 2007):
• As soon as you can, reflect on and improve your notes by filling in gaps, completing thoughts, and looking for connections
among ideas.
• Remember to link new ideas to what you already know.
• Summarize your notes. Boil them down and organize them.
• After each class session, write down at least seven major ideas,
definitions, or details that are likely to become test questions.
Then make up questions from your notes and be sure you can
answer them.
Summary
The letters LISAN are a guide to active listening, but listening and
good note taking are not enough. You must also review, organize,
reflect, extend, and think about new ideas. Use active listening to
get involved in your classes and you will undoubtedly learn more
(Rowe, 2007).
Study Strategies —
Making a Habit of Success
Grades depend as much on effort as they do on “intelligence.”
However, don’t forget that good students work more efficiently,
not just harder. Many study practices are notoriously poor, such
as recopying lecture notes, studying class notes but not the textbook (or the textbook but not class notes), outlining chapters,
answering study questions with the book open, and “group study”
(which often becomes a party). The best students emphasize quality: They study their books and notes in depth and attend classes
regularly. It’s a mistake to blame poor grades on events “beyond
your control.” Students who are motivated to succeed usually get
better grades (Perry et al., 2001). Let’s consider a few more things
you can do to improve your study habits.
The Psychology of Studying
5
Study in a Specific Place
Test Yourself
Ideally, you should study in a quiet, well-lit area free of distractions. If possible, you should also have at least one place where you
only study. Do nothing else at that spot: Keep magazines, MP3
players, friends, cell phones, pets, posters, video games, puzzles,
food, lovers, sports cars, elephants, pianos, televisions, YouTube,
kazoos, and other distractions out of the area. In this way, the
habit of studying will become strongly linked with one specific
place. Then, rather than trying to force yourself to study, all you
have to do is go to your study area. Once there, you’ll find it is
relatively easy to get started.
A great way to improve grades is to take practice tests before the real
one in class. In other words, studying should include self-testing, in
which you pose questions to yourself. You can use flash cards, Learning Check questions, online quizzes, a study guide, or other means.
As you study, ask many questions and be sure you can answer them.
Studying without self-testing is like practicing for a basketball game
without shooting any baskets.
For more convenient self-testing, your professor may make a
Study Guide or a separate booklet of Practice Quizzes available. You
can use either to review for tests. Practice quizzes are also available
on the book companion website, as described later. However, don’t
use practice quizzes as a substitute for studying your textbook and
lecture notes. Trying to learn from quizzes alone will probably
lower your grades. It is best to use quizzes to find out what topics
you need to study more (Brothen & Wambach, 2001).
Use Spaced Study Sessions
It is reasonable to review intensely before an exam. However,
you’re taking a big risk if you are only “cramming” (learning new
information at the last minute). Spaced practice is much more
efficient (Anderson, 2005). Spaced practice consists of a large
number of relatively short study sessions. Long, uninterrupted
study sessions are called massed practice. (If you “massed up” your
studying, you probably messed it up too.)
Cramming places a big burden on memory. Usually, you
shouldn’t try to learn anything new about a subject during the last
day before a test. It is far better to learn small amounts every day
and review frequently (Anderson, 2005).
Overlearn
Many students underprepare for exams, and most overestimate how
well they will do. A solution to both problems is overlearning,
in which you continue studying beyond your initial mastery of a
topic. In other words, plan to do extra study and review after you
think you are prepared for a test. One way to overlearn is approach
all tests as if they will be essays. That way, you will learn more completely, so you really “know your stuff.”
Try Mnemonics
Learning has to start somewhere, and memorizing is often the first
step. Many of the best ways to improve memory are covered in
Chapter 8. Let’s consider just one technique here.
A mnemonic (nee-MON-ik) is a memory aid. There are many
ways to create mnemonics. Most mnemonics link new information to ideas or images that are easy to remember. For example,
what if you want to remember that the Spanish word for duck is
pato (pronounced POT-oh)? To use a mnemonic, you could picture a duck in a pot or a duck wearing a pot for a hat. Likewise, to
remember that the cerebellum controls coordination, you might
picture someone named “Sarah Bellum” who is very coordinated.
For best results, make your mnemonic images exaggerated or
bizarre, vivid, and interactive (Macklin & McDaniel, 2005).
Self-Regulated Learning —
Academic All-Stars
Think of a topic you are highly interested in, such as music, sports,
fashion, cars, cooking, politics, or movies. Whatever the topic,
you have probably learned a lot about it — painlessly. How could
you make your college work more like voluntary learning? An
approach called self-regulated learning might be a good start. Selfregulated learning is deliberately reflective and active, self-guided
study (Hofer & Yu, 2003). Here’s how you can change passive
studying into goal-oriented learning:
1. Set specific, objective learning goals. Try to begin each learning
session with specific goals in mind. What knowledge or skills
are you trying to master? What do you hope to accomplish
(Knaus & Ellis, 2002)?
Spaced practice Practice spread over many relatively short study
sessions.
Massed practice Practice done in a long, uninterrupted study session.
Mnemonic A memory aid or strategy.
Self-testing Evaluating learning by posing questions to yourself.
Mnemonics make new information more familiar and memorable. Forming an
image of a duck wearing a pot for a hat might help you remember that pato is
the Spanish word for duck.
Overlearning Continuing to study and learn after you think you’ve
mastered a topic.
Self-regulated learning Deliberately reflective and active, self-guided
study.
6
INTRODUCTION
2. Plan a learning strategy. How will you accomplish your goals?
Make daily, weekly, and monthly plans for learning. Then
put them into action.
3. Be your own teacher. Effective learners silently give themselves
guidance and ask themselves questions. For example, as you
are learning, you might ask yourself, “What are the important ideas here? What do I remember? What don’t I understand? What do I need to review? What should I do next?”
4. Monitor your progress. Self-regulated learning depends on
self-monitoring. Exceptional learners keep records of their
progress toward learning goals (pages read, hours of studying, assignments completed, and so forth). They quiz themselves, use study guides, make sure they follow the SQ4R
system, and find other ways to check their understanding
while learning.
5. Reward yourself. When you meet your daily, weekly, or
monthly goals, reward your efforts in some way, such as
going to a movie or downloading some new music. Be
aware that self-praise also rewards learning. Being able to
say, “Hey, I did it!” or “Good work!” and knowing that you
deserve it can be very rewarding. In the long run, success,
self-improvement, and personal satisfaction are the real
payoffs for learning.
6. Evaluate your progress and goals. It is a good idea to frequently
evaluate your performance records and goals. Are there specific areas of your work that need improvement? If you are
not making good progress toward long-range goals, do you
need to revise your short-term targets?
7. Take corrective action. If you fall short of your goals you may
need to adjust how you budget your time. You may also need
to change your learning environment to deal with distractions such as watching TV, daydreaming, talking to friends,
or testing the structural integrity of the walls with your stereo
system.
If you discover that you lack necessary knowledge or skills, ask
for help, take advantage of tutoring programs, or look for information beyond your courses and textbooks. Knowing how to regulate
and control learning can be a key to lifelong enrichment and personal empowerment.
Procrastination — Avoiding
the Last-Minute Blues
All of these study techniques are fine. But what can I do about
procrastination? A tendency to procrastinate is almost universal.
(When campus workshops on procrastination are offered, many
students never get around to signing up!) Even when procrastination doesn’t lead to failure, it can cause much suffering. Procrastinators work only under pressure, skip classes, give false reasons
for late work, and feel ashamed of their last-minute efforts. They
also tend to feel frustrated, bored, and guilty more often (Blunt &
Pychyl, 2005).
Why do so many students procrastinate? Many students equate
grades with their personal worth. That is, they act as if grades tell
whether they are good, smart people who will succeed in life. By
procrastinating they can blame poor work on a late start, rather
than a lack of ability (Beck, Koons, & Milgrim, 2000). After all, it
wasn’t their best effort, was it?
Perfectionism is a related problem. If you expect the impossible, it’s hard to start an assignment. Students with high standards
often end up with all-or-nothing work habits (Onwuegbuzie,
2000).
Time Management
Most procrastinators must eventually face the self-worth issue.
Nevertheless, most can improve by learning study skills and better
time management. We have already discussed general study skills,
so let’s consider time management in a little more detail.
A weekly time schedule is a written plan that allocates time for
study, work, and leisure activities. To prepare your schedule, make
a chart showing all the hours in each day of the week. Then fill in
times that are already committed: sleep, meals, classes, work, team
practices, lessons, appointments, and so forth. Next, fill in times
when you will study for various classes. Finally, label the remaining
hours as open or free times.
Each day, you can use your schedule as a checklist. That way
you’ll know at a glance which tasks are done and which still need
attention (Knaus & Ellis, 2002).
You may also find it valuable to make a term schedule that
lists the dates of all quizzes, tests, reports, papers, and other major
assignments for each class.
The beauty of sticking to a schedule is that you know you are
making an honest effort. It will also help you avoid feeling bored
while you are working or guilty when you play.
Be sure to treat your study times as serious commitments, but
respect your free times, too. And remember, students who study
hard and practice time management do get better grades (Rau &
Durand, 2000).
Goal Setting
As mentioned earlier, students who are active learners set specific
goals for studying. Such goals should be clear-cut and measurable (Knaus & Ellis, 2002). If you find it hard to stay motivated,
try setting goals for the semester, the week, the day, and even
for single study sessions. Also, be aware that more effort early
in a course can greatly reduce the “pain” and stress you will
experience later. If your professors don’t give frequent assignments, set your own day-by-day goals. That way, you can turn big
assignments into a series of smaller tasks that you can actually
complete (Ariely & Wertenbroch, 2002). An example would
be reading, studying, and reviewing 8 pages a day to complete
a 40-page chapter in 5 days. For this textbook, reading from
one Knowledge Builder to the next each day might be a good
pace. Remember, many small steps can add up to an impressive
achievement.
The Psychology of Studying
Study Skills Checklist
Time Management
Make formal schedule
Set specific goals
Study Habits
Study in specific area
Pace study and review
Create memory aids
Test yourself
Overlearn
Reading
Use SQ4R method
Study while reading
Review frequently
Note Taking
Listen actively
Use LISAN method
Review notes frequently
• Figure I.2 Study skills checklist.
Make Learning an Adventure
A final point to remember is that you are most likely to procrastinate if you think a task will be unpleasant (Pychyl et al., 2000).
Learning can be hard work. Nevertheless, many students find ways
to make schoolwork interesting and enjoyable. Try to approach
your schoolwork as if it were a game, a sport, an adventure, or simply a way to become a better person. The best educational experiences are challenging yet fun (Ferrari & Scher, 2000).
Virtually every topic is interesting to someone, somewhere. You
may not be particularly interested in the sex life of South American tree frogs. However, a biologist might be fascinated. (Another
tree frog might be, too.) If you wait for teachers to “make” their
courses interesting, you are missing the point. Interest is a matter
of your attitude. (See Figure I.2 for a summary of study skills.)
•
Taking Tests — Are You “Test Wise”?
If I read and study effectively, is there anything else I can do to improve
my grades? You must also be able to show what you know on tests.
Here are some suggestions for improving your test-taking skills:
General Test-Taking Skills
4. Be sure to answer all questions.
5. Use your time wisely.
6. Ask for clarification when necessary.
Objective Tests
Several additional strategies can help you do better on objective tests. Objective tests (multiple-choice and true–false items)
require you to recognize a correct answer among wrong ones or a
true statement versus a false one. Here are some strategies for taking objective tests:
1. First, relate the question to what you know about the topic.
Then, read the alternatives. Does one match the answer you
expected to find? If none match, reexamine the choices and
look for a partial match.
2. Read all the choices for each question before you make a
decision. Here’s why: If you immediately think that a is correct and stop reading, you might miss seeing a better answer
like “both a and d.”
3. Read rapidly and skip items you are unsure about. You may
find “free information” in later questions that will help you
answer difficult items.
4. Eliminate certain alternatives. With a four-choice multiplechoice test, you have one chance in four of guessing right.
If you can eliminate two alternatives, your guessing odds
improve to 50-50.
5. Unless there is a penalty for guessing, be sure to answer any
skipped items. Even if you are not sure of the answer, you
may be right. If you leave a question blank, it is automatically
wrong. When you are forced to guess, don’t choose the longest answer or the letter you’ve used the least. Both strategies
lower scores more than random guessing does.
6. There is a bit of folk wisdom that says “Don’t change your
answers on a multiple-choice test. Your first choice is usually
right.” This is false. If you change answers, you are more likely
to gain points than to lose them. This is especially true if you
are uncertain of your first choice or it was a hunch, and if
your second choice is more reflective (Higham & Gerrard,
2005).
7. Remember, you are searching for the one best answer to
each question. Some answers may be partly true, yet flawed
in some way. If you are uncertain, try rating each multiplechoice alternative on a 1–10 scale. The answer with the highest rating is the one you are looking for.
8. Few circumstances are always or never present. Answers that
include superlatives such as most, least, best, worst, largest, or
smallest are often false.
You’ll do better on all types of tests if you observe the following
guidelines (Wood & Willoughby, 1995):
1. Read all directions and questions carefully. They may give
you good advice or clues.
2. Quickly survey the test before you begin.
3. Answer easy questions before spending time on more difficult ones.
7
Weekly time schedule A written plan that allocates time for study,
work, and leisure activities during a 1-week period.
Term schedule A written plan that lists the dates of all major
assignments for each of your classes for an entire semester or quarter.
Specific goal A goal with a clearly defined and measurable outcome.
8
INTRODUCTION
Essay Tests
Essay questions are a weak spot for students who lack organization,
don’t support their ideas, or don’t directly answer the question
(Rowe, 2007). When you take an essay exam try the following:
1. Read the question carefully. Be sure to note key words, such
as compare, contrast, discuss, evaluate, analyze, and describe.
These words all demand a certain emphasis in your answer.
2. Answer the question. If the question asks for a definition and
an example, make sure you provide both. Providing just a
definition or just an example will get you half marks. Giving
three examples instead of the one asked for will not earn you
any extra marks.
3. Think about your answer for a few minutes and list the main
points you want to make. Just write them as they come to
mind. Then rearrange the ideas in a logical order and begin
writing. Elaborate plans or outlines are not necessary.
4. Don’t beat around the bush or pad your answer. Be direct.
Make a point and support it. Get your list of ideas into words.
5. Look over your essay for errors in spelling and grammar. Save
this for last. Your ideas are of first importance. You can work
on spelling and grammar separately if they affect your grades.
Short-Answer Tests
Tests that ask you to fill in a blank, define a term, or list specific
items can be difficult. Usually, the questions themselves contain
little information. If you don’t know the answer, you won’t get
much help from the questions.
The best way to prepare for short-answer tests is to overlearn
the details of the course. As you study, pay special attention to lists
of related terms.
Again, it is best to start with the questions you’re sure you
know. Follow that by completing items you think you probably
know. Questions you have no idea about can be left blank.
Again, for your convenience, Figure I.2 provides a checklist
summary of the main study skills we have covered.
“pages.” If you know the URL (or “address”) of a website, you can
view the information it contains. Almost all web pages also have
links to other websites. These links let you “jump” from one site
to the next to find more information.
Google It
To find psychological information on the Internet, you’ll need a
computer and an Internet connection. If you don’t own a computer, you can usually use one on campus. Various software browsers make it easier to navigate around the web. A browser allows
you to see text, images, sounds, and video clips stored on other
computers. Browsers also keep lists of your favorite URLs so that
you can return to them.
The Book Companion Website
How would I find information about psychology on the Internet?
Your first stop on the Internet should be the book companion
website. Here’s what you’ll find there:
Online Quizzes. You can use these chapter-by-chapter
multiple-choice and true–false quizzes to practice for
tests and check your understanding.
Web Links. This area is a “launching pad” that will take you
to other psychology-related sites on the Internet. If a site
sounds interesting, a click of the mouse will take you to it.
Online Flash Cards. These online flash cards allow you to
practice terms and concepts interactively.
Crossword Puzzles. Crosswords are a fun way to check your
knowledge of key terms and their definitions.
The book companion website is located at www.cengage.com/
psychology/coon. Be sure to visit this site for valuable information
about how to improve your grades and enhance your appreciation
of psychology.
•
Using Digital Media —
Netting New Knowledge
Google any psychological term ranging from amnesia to zoophobia
and you will find a vast library of information, from serious websites, like that maintained by the American Psychological Association, to Wikipedia entries and personal blogs. Even if you don’t
own a computer, you can usually use one on campus to learn more
about psychology. However, be aware that information on the
Internet is not always accurate. It is wise to approach all websites
with a healthy dose of skepticism.
Digital Gateways
The Internet is a network of interlinked computers. An important subpart of the Internet is the World Wide Web (WWW)
or just plain “web,” an interlinked system of information “sites” or
The book companion website gives you online access to a variety of valuable
learning aids and interesting materials.
The Psychology of Studying
9
• Figure I.3 A sample screen from CengageNOW.
CengageNOW
Students can also make use of CengageNOW for Coon/Mitterer’s
Psychology: Gateways to Mind and Behavior, twelfth edition, a
web-based, personalized study system that provides a pre-test and
a post-test for each chapter. CengageNOW, located at academic
.cengage.com/login, also creates personalized study plans — which
include rich media such as videos, animations, and learning modules and links to the eBook that help you study the specific topics
in the text where you need to study most ( Figure I.3).
•
Wadsworth’s Psychology Resource Center
Do you like videos, simulations, and animations? Do you learn
best when you get actively involved in psychology? The Wadsworth Psychology Resource Center brings psychology to life
with a full library of original and classic video clips plus interactive
learning modules tied to all of the topics covered in your introductory psychology course. Log in at www.cengage.com/login to visit
the resource center.
•
Figure I.4 This is a sample abstract from the PsycINFO database. If you search for
the term study skills, you will find this article and many more in PsycINFO. (Reproduced
with permission of the American Psychological Association, publisher of the PsycINFO database.
PsycINFO Database Record © 2007 APA, all rights reserved. No further reproduction or distribution is
permitted without written permission from the American Psychological Association.)
ics by entering words such as drug abuse, postpartum depression, or
creativity.
You can gain access to PsycINFO in several ways. Almost every
college and university subscribes to PsycINFO. If this is the case,
you can usually search PsycINFO from a terminal in your college
library or computer center for free. PsycINFO can also be directly
accessed (for a fee) through the Internet via APA’s PsycINFO
Direct service. For more information on how to gain access to
PsycINFO, check this website: www.apa.org/psycinfo.
The APA Website
Psychology Websites
You’ll find the titles of interesting websites you may want to
explore at the end of each chapter in this book, including this one.
The best way to reach these sites is through the book companion
website. We have not included website addresses in the book
because they often change or may become inactive. At the website
you’ll find up-to-date links for websites listed in this book. The
sites we’ve listed are generally of high quality. However, be aware
that information on the Internet is not always accurate. It is wise to
approach all websites with a healthy dose of skepticism.
The APA also maintains an online library of general interest
articles on aging, anger, children and families, depression, divorce,
emotional health, kids and the media, sexuality, stress, testing
issues, women and men, and other topics. They are well worth
consulting when you have questions about psychological issues.
You’ll find them at www.apa.org. For links to recent articles in
newspapers and magazines, be sure to check the APA’s PsycPORT
page at www.psycport.com.
Internet An electronic network of interlinked computers.
PsycINFO
Psychological knowledge can also be found through specialized
online databases. One of the best is PsycINFO, offered by the American Psychological Association. PsycINFO provides summaries of
the scientific and scholarly literature in psychology. Each record in
PsycINFO consists of an abstract (short summary), plus notes about
the author, title, source, and other details ( Figure I.4). All entries
are indexed using key terms. Thus, you can search for various top-
•
World Wide Web (WWW) A system of information sites accessible
through the Internet.
Links Connections built into websites that let you “jump” from one site
to the next.
Browser Software that facilitates access to text, images, sounds, video,
and other information stored in formats used on the Internet.
PsycINFO A searchable, online database that provides brief summaries
of the scientific and scholarly literature in psychology.
INTRODUCTION
Please do take some of the “digital gateways” described here.
You might be surprised by the fascinating information that awaits
you. Investigating psychology on your own is one of the best ways
to enrich an already valuable course.
A Final Word
There is a distinction in Zen between “live words” and “dead
words.” Live words come from personal experience; dead words
are “about” a subject. This book can only be a collection of dead
words unless you accept the challenge of taking an intellectual step
through this gateway to psychology. You will find many helpful,
useful, and exciting ideas in the pages that follow. To make them
yours, you must set out to actively learn as much as you can. The
ideas presented here should get you off to a good start. Good
luck!
For more information, consult any of the following books:
Hettich, P. I. (2005). Connect college to career: Student guide to
work and life transition. Belmont, CA: Wadsworth.
Knaus, W. J., & Ellis, A. (2002). The procrastination workbook:
Your personalized program for breaking free from the patterns
that hold you back. Oakland, CA: New Harbinger Press.
Rosnow, R. L. (2006). Writing papers in psychology: A student
guide to research papers, essays, proposals, posters, and handouts (7th ed.). Belmont, CA: Wadsworth.
Rowe, B. (2007). College awareness guide: What students
need to know to succeed in college. Upper Saddle River, NJ:
Prentice Hall.
Santrock, J. W., & Halonen, J. S. (2007). Connections to college
success. Belmont, CA: Wadsworth.
Relate
Which study skills do you think would help you the most? Which techniques do you already use? Which do you think you should try? To what
extent do you already engage in self-regulated learning? What additional
steps could you take to become a more active, goal-oriented learner?
Answers: 1. T 2. F 3. T 4. F 5. T 6. self-regulated 7. T 8. Both encourage
people to actively seek information as a way of learning more effectively.
10
Web Resources
For an up-to-date list of direct links to interesting sites, including
those listed here, visit the student companion site for this book at
www.cengage.com/psychology/coon
How to Succeed as a Student Advice on how to be a college student.
Topics from studying to housing to preparation for work are included.
Library Research in Psychology Hints on how to do library research
in psychology.
Psychology Glossary You can use this glossary to get additional definitions for common psychological terms.
Study Skills More information on SQ4R, taking tests, note taking, and
time management.
Interactive Learning
Introduction to Psychology: Gateways to Mind and Behavior Book
Companion Website
www.cengage.com/psychology/coon
K NOW LED G E B U I L D E R
Study Skills
Visit your book companion website, where you will find flash cards,
practice quizzes, web links, and more to help you study.
RECITE
1. The four Rs in SQ4R stand for “read, recite, reflect, and review.” T or F?
2. When using the LISAN method, students try to write down as much
of a lecture as possible so that their notes are complete. T or F?
3. Spaced study sessions are usually superior to massed practice.
T or F?
4. According to research, you should almost always stick with your first
answer on multiple-choice tests. T or F?
5. To use the technique known as overlearning, you should continue to
study after you feel you have begun to master a topic. T or F?
6. Setting learning goals and monitoring your progress are important
parts of ______________________________ learning.
7. Procrastination is related to seeking perfection and equating selfworth with grades. T or F?
REFLECT
Critical Thinking
8. How are the SQ4R method and the LISAN method related?
Just what you need to know NOW!
Spend time on what you need to master rather than on information you already have learned. Take a pre-test for this chapter, and
CengageNOW will generate a personalized study plan based on
your results. The study plan will identify the topics you need to
review and direct you to online resources to help you master those
topics. You can then take a post-test to help you determine the
concepts you have mastered and what you will need to work on.
Try it out! Go to www.cengage.com/login to sign in with an access
code or to purchase access to this product.
CHAPTER
1
Introduction to Psychology
and Research Methods
Gateway Theme
Psychology is a science and a profession. Scientific observation is the most powerful way to
answer questions about behavior.
Mike Nelson/AFP/Getty Images
Gateway Questions
• What is psychology, and what are its goals?
• What is critical thinking?
• How does psychology differ from false explanations of
behavior?
•
How is the scientific method applied in psychological
research?
•
•
How did the field of psychology emerge?
•
•
•
•
What are the major specialties in psychology?
•
How good is the psychological information found in the
popular media?
How is an experiment performed?
What is a double-blind experiment?
What nonexperimental research methods do
psychologists use?
What are the contemporary perspectives in psychology?
11
preview
Wondering About Human Behavior
Near the end of every summer, a remote stretch of Nevada desert hosts Burning Man, an eclectic weeklong festival attended
by tens of thousands of, well, unusual folks. It’s hard to explain
just what this unique event is about except to say that attendees are encouraged to openly express themselves in any way
they see fit. (Feel free to unleash your imagination on this one.)
Revelers participate in a riotous cultural experience that climaxes with the burning of a giant wicker man. Old hippies mix
with self-described rednecks, performance artists, musicians,
sun worshippers, and individualists of every stripe.
Why, you might wonder, do people go to Burning Man, some
of them year after year? But then again, you might equally wonder why people join the Army, or get married, or travel to different countries, or become suicide bombers, or live out their
lives in monasteries, or go to school. You might even wonder, at
least sometimes, why you do what you do. In other words, just
like your authors, the odds are you are curious about human
behavior. That may even be a part of the reason you are taking
a course in psychology and reading this book.
Look around you: The Internet, television, newspapers,
radio, and magazines are brimming with psychological topics. Psychology is an ever-changing panorama of people and
ideas. You really can’t call yourself educated without knowing
something about it. And, although we might envy those who
have walked on the moon or explored the ocean’s depths, the
ultimate frontier lies much closer to home. Psychology can help
you better understand yourself and others. This book is a guided
tour of human behavior. We hope you enjoy the adventure.
Gateway Question: What is psychology, and what are its goals?
People have always been curious about human behavior. The
word psychology itself is thousands of years old, coming from the
ancient Greek roots psyche, which means “mind,” and logos, meaning “knowledge or study.” However, have you ever actually seen
or touched a “mind”? Because the mind can’t be studied directly,
psychology is now defined as the scientific study of behavior and
mental processes.
What does behavior refer to in the definition of psychology? Anything you do — eating, hanging out, sleeping, talking, or sneezing — is a behavior. So are studying, snowboarding, gambling,
watching television, tying your shoelaces, wrapping presents,
learning Spanish, and reading this book. Naturally, we are interested in overt behaviors (directly observable actions and responses).
But psychologists also study covert behaviors. These are private,
internal activities, such as thinking, dreaming, remembering, and
other mental events ( Jackson, 2008).
All in all, then, psychology studies behaviors from A to Z:
aging, burnout, conformity, death, emotion, flexibility, groupthink, hypnosis, intelligence, joy, kinesthesis, love, memory, noise
pollution, originality, personality, quantitative reasoning, repression, sexuality, therapy, unconscious, wisdom, vision, xenophobia,
youth, zeitgeist, and much more.
Today, psychology is both a science and a profession. As scientists, some psychologists do research to discover new knowledge.
Others are teachers who share their knowledge with students. Still
others apply psychology to solve problems in mental health, education, business, sports, law, and medicine (Coolican et al., 2007).
Later we will return to the profession of psychology. For now, let’s
focus on how knowledge is created. Whether they work in a class12
Picture Partners/Alamy
Psychology — The ABCs of Behavior
Psychologists are highly trained professionals. In addition to the psychological
knowledge they possess, psychologists learn specialized skills in counseling and
therapy, measurement and testing, research and experimentation, statistics,
diagnosis, treatment, and many other areas.
room, a lab, or a clinic, all psychologists rely on critical thinking
and information gained from scientific research.
Seeking Empirical Evidence
Many people regard themselves as expert “people watchers” and
form their own “common-sense” theories of behavior. However,
you may be surprised to learn how often self-appointed authorities and common-sense beliefs are wrong. Check your own expertise about human behavior by reading “Testing Common-Sense
Beliefs.”
Because of the limitations of common sense, psychologists
have a special respect for scientific observation, which is based
Introduction to Psychology and Research Methods
13
CRIT ICA L T H I N KI N G
Testing Common-Sense Beliefs
•
•
•
Babies love their mothers because mothers fulfill their babies’ physiological need
for food. True or False?
Most humans use only 10 percent of
their potential brainpower. True or False?
Blind people have unusually sensitive
organs of touch. True or False?
•
•
•
•
•
The more motivated you are, the better
you will do at solving a complex problem.
True or False?
The major cause of forgetting is that
memory traces decay or fade as time
passes. True or False?
Psychotherapy has its greatest success in
the treatment of psychotic patients who
have lost touch with reality. True or False?
Personality tests reveal your basic
motives, including those you may not be
aware of having. True or False?
To change people’s behavior toward members of ethnic minority groups, we must
first change their attitudes. True or False?
on gathering empirical evidence (information gained from direct
observation). Unlike personal observation, scientific observation
is systematic and intersubjective. In other words, observations are
planned and they can be confirmed by more than one observer.
Basically, the empirical approach says, “Let’s take a more objective
look” (Stanovich, 2007). We study behavior directly and collect
data (observed facts) so that we can draw valid conclusions. Would
you say it’s true, for instance, that “Absence makes the heart grow
fonder”? Why argue about it? As psychologists, we would simply
get some people who are separated (“absent hearts”) and some
who see each other every day (“present hearts”) and find out who
is fonder of their loved ones!
Here’s an example of gathering empirical evidence: Have you
ever wondered if people become more hostile when it’s boiling hot
outside? John Simister and Cary Cooper (2005) decided to find
out. They obtained data on temperatures and criminal activity in
•
9%
8%
7%
Jul. 1996
Jan. 1996
Jul. 1995
Jan. 1995
Jul. 1994
Jan. 1994
Jul. 1993
Aggravated assault, % of year (left-hand scale)
Temperature in LA (right-hand scale)
Jan. 1993
Aggravated assault, % of year
10%
6%
Actually research has shown that all these
beliefs are false. Yet in a survey, all the beliefs
were accepted as common sense by many
college students (Landau & Bavaria, 2003).
How did you do?
We can all benefit from being more reflective as we evaluate our beliefs. It’s valuable
to think critically and ask whether a belief
makes logical sense. Do any of the concepts
in this book apply to the belief? Can you
imagine how you could collect evidence that
might get you closer to the truth? Critical
Thinking boxes like this one will help you be
more reflective as you think critically about
human behavior.
Los Angeles over a 4-year period. When they graphed air temperature and the frequency of aggravated assaults, a clear relationship
emerged ( Figure 1.1). Assaults and temperatures rise and fall
more or less in parallel (so there may be something to the phrase
“hot under the collar”).
Isn’t the outcome of this study fairly predictable? Not if you started
out believing otherwise. Sometimes the results of studies match our
personal observations and common-sense beliefs and sometimes
they come as a surprise. In this instance, you may have guessed the
outcome. Your suspicions were confirmed by scientific observation. However, hostile actions that require more extreme physical
exertion, such as fistfights, might become less likely at very high
temperatures. Without systematically gathering data, we wouldn’t
know for sure if overheated Angelenos become more lethargic or
more aggressive when it gets hot. Thus, the study tells us something
interesting about frustration, discomfort, and aggression.
43
40
37
34
31
28
25
22
19
16
13
10
7
4
1
2
5
8
11
14
17
1.1 Results of an empirical study. The graph shows
•thatFigure
aggravated assaults in Los Angeles become more likely as
Temperature in Los Angeles
It may appear that psychological research
“discovers” what we already know from everyday experience. Why waste time and money
confirming the obvious? Actually, commonsense beliefs are often wrong. See if you can
tell which of the following common-sense
beliefs are wrong (Landau & Bavaria, 2003):
air temperature increases. This suggests that physical discomfort
is associated with interpersonal hostility. (Data from Simister &
Cooper, 2005.)
Psychology The scientific study of behavior and
mental processes.
Scientific observation An empirical investigation
structured to answers questions about the world in a
systematic and intersubjective fashion (observations
can be reliably confirmed by multiple observers).
14
CHAPTER 1
The scientific study of dreaming was made possible by use of the EEG, a device that
records the tiny electrical signals generated by the brain as a person sleeps. The EEG
converts these electrical signals into a written record of brain activity. Certain shifts
in brain activity, coupled with the presence of rapid eye movements, are strongly
related to dreaming. (See Chapter 6, pages 186–188, for more information.)
Psychological Research
Many fields, such as history, law, art, and business, are also interested in human behavior. How is psychology different? Psychology’s great strength is that it uses scientific observation to systematically answer questions about behavior (Stanovich, 2007). Of
course, it may be impractical or unethical to study some topics.
More often, questions go unanswered for lack of a suitable
research method (a systematic process for answering scientific
questions). In the past, for example, we had to take the word
of people who say they never dream. Then the EEG (electroencephalograph, or brain-wave machine) was invented. Certain
EEG patterns, and the presence of eye movements, can reveal
that a person is dreaming. People who “never dream,” it turns
out, dream frequently. If they are awakened during a dream, they
vividly remember it. Thus, the EEG helped make the study of
dreaming more scientific.
Research Specialties
What kinds of topics do psychologists study? Here’s a sample of what
various psychologists might say about their work:
“I’m a personality theorist. I study personality traits, motivation, and individual differences. I am especially interested in the personality profiles of
highly creative college students.”
“In general, developmental psychologists study the course of human
growth and development, from conception until death. I’m especially interested in the transition from the teenage years to early adulthood.”
“Like other learning theorists, I study how and why learning occurs in
humans and animals. Right now I’m investigating how patterns of punishment affect learning.”
“As a sensation and perception psychologist, I investigate how we discern
the world through our senses. I am using a perceptual theory to study how
we are able to recognize faces in a crowd.”
“Comparative psychologists study and compare the behavior of different
species, especially animals. Personally, I’m fascinated by the communication
abilities of porpoises.”
“Cognitive psychologists are primarily interested in thinking. I want to
know how reasoning, problem solving, memory, and other mental processes relate to computer game playing.”
“Biopsychologists are interested in how behavior relates to biological
processes, especially activities in the nervous system. I’ve been doing some
exciting research on how the brain controls hunger.”
“Gender psychologists study differences between females and males.
I want to understand how gender differences are influenced by biology,
child rearing, education, and stereotypes.”
“Social psychologists explore human social behavior, such as attitudes,
persuasion, riots, conformity, leadership, racism, and friendship. My own
interest is interpersonal attraction. I place two strangers in a room and analyze how strongly they are attracted to each other.”
“Evolutionary psychologists are interested in how our behavior is
guided by patterns that evolved during the long history of humankind. I am studying some interesting trends in male and female mating
choices.”
“Cultural psychologists study the ways in which culture affects human
behavior. The language you speak, the foods you eat, how your parents
disciplined you, what laws you obey, who you regard as ‘family,’ whether
you eat with a spoon or your fingers — these and countless other details of
behavior are strongly influenced by culture.”
“Forensic psychologists apply psychological principles to legal issues. I
am interested in improving the reliability of eyewitness testimony during
trials.”
This small sample should give you an idea of the diversity of
psychological research. It also hints at some of the information we
will explore in this book.
Animals and Psychology
Research involving animals was mentioned in some of the preceding
examples. Why is that? You may be surprised to learn that psychologists are interested in the behavior of any living creature — from
flatworms to humans. Indeed, some comparative psychologists
spend their entire careers studying rats, cats, dogs, parrots, or
chimpanzees.
Although only a small percentage of psychological studies
involve animals, they include many different types of research
(Ord et al., 2005). Some psychologists use animal models to
discover principles that apply to humans. For instance, animal
studies have helped us understand stress, learning, obesity, aging,
sleep, and many other topics. Psychology also benefits animals.
For example, caring for domestic animals, as well as endangered
species in zoos, relies on behavioral studies.
Introduction to Psychology and Research Methods
15
bridges
Bystander apathy and conditions that influence whether
people will help in an emergency are of great interest to social
psychologists. See Chapter 17, pages 564–566 for details.
Ron Cohn/The Gorilla Foundation
Prediction
Some of the most interesting research with animals has focused on attempts
to teach primates to communicate with sign language. Psychologist Penny
Patterson has spent 35 years teaching Koko more than 1,000 signs. One of Koko’s
favorite signs (“stink”) is shown here. (To learn more, visit www.koko.org.) Such
research has helped illuminate the origins of human language and has even suggested better methods for teaching language to children with serious language
impairment. (See Chapter 9, pages 291–292, for more information.)
Psychology’s third goal, prediction, is the ability to forecast
behavior accurately. Notice that our explanation of bystander apathy makes a prediction about the chances of getting help. If you’ve
ever been stranded on a busy freeway with car trouble, you’ll
recognize the accuracy of this prediction: Having many potential
helpers nearby is no guarantee that anyone will stop to help.
Control
Description, explanation, and prediction seem reasonable, but is control a valid goal? “Control” may seem like a threat to personal freedom. However, to a psychologist, control simply refers to altering
conditions that affect behavior. If a clinical psychologist helps a
person overcome a terrible fear of spiders, control is involved. If
Psychology’s Goals
Charles Gupton/Stock Boston
What do psychologists hope to achieve? Psychology’s ultimate goal is
to benefit humanity (O’Neill, 2005). Specifically, the goals of the
science of psychology are to describe, understand, predict, and control
behavior. What do psychology’s goals mean in practice? Let’s see.
Description
Answering psychological questions often begins with a careful
description of behavior. Description, or naming and classifying, is
typically based on making a detailed record of scientific observations.
But a description doesn’t explain anything, does it? Right. Useful
knowledge begins with accurate description, but descriptions fail
to answer the important “why” questions. Why do more women
attempt suicide, and why do more men complete it? Why are
people more aggressive when they are uncomfortable? Why are
bystanders often unwilling to help in an emergency?
Understanding
We have met psychology’s second goal when we can explain an
event. That is, understanding usually means we can state the
causes of a behavior. For example, research on “bystander apathy”
reveals that people often fail to help when other possible helpers
are nearby. Why? Because a “diffusion of responsibility” occurs.
Basically, no one feels personally obligated to pitch in. As a result,
the more potential helpers there are, the less likely it is that anyone
will help (Darley, 2000; Darley & Latané, 1968). Now we can
explain a perplexing problem.
Some psychologists specialize in administering, scoring, and interpreting psychological tests, such as tests of intelligence, creativity, personality, or aptitude.
This specialty, which is called psychometrics, is an example of using psychology
to predict future behavior.
Research method A systematic approach to answering scientific
questions.
Animal model In research, an animal whose behavior is used to derive
principles that may apply to human behavior.
Description In scientific research, the process of naming and
classifying.
Understanding In psychology, understanding is achieved when the
causes of a behavior can be stated.
Prediction An ability to accurately forecast behavior.
Control Altering conditions that influence behavior.
16
CHAPTER 1
you suggest changes in a classroom that help students learn better,
you have exerted control. Control is also involved in designing
automobiles to keep drivers from making fatal errors. Clearly, psychological control must be used wisely and humanely.
In summary, psychology’s goals are a natural outgrowth of our
desire to understand behavior. Basically, they boil down to asking
the following questions:
What is the nature of this behavior? (description)
Why does it occur? (understanding and explanation)
Can we forecast when it will occur? (prediction)
What conditions affect it? (control)
K NOW LED G E B U I L D E R
The Science of Psychology
RECITE
To check your memory, see if you can answer these questions. If you miss any,
skim over the preceding material before continuing to make sure you understand what you just read.
1. Psychology is the ___________________ study of _______________
and ____________ processes.
2. The best psychological information is typically based on
a. proven theories
b. opinions of experts and authorities
c. anthropomorphic measurements
d. empirical evidence
3. In psychological research, animal _________________ may be used
to discover principles that apply to human behavior.
4. Which of the following questions relates most directly to the goal of
understanding behavior?
a. Do the scores of men and women differ on tests of thinking
abilities?
b. Why does a blow to the head cause memory loss?
c. Will productivity in a business office increase if room temperature is raised or lowered?
d. What percentage of college students suffer from test anxiety?
Match the following research areas with the topics they cover.
_____ 5. Developmental psychology A. Attitudes, groups, leadership
_____ 6. Learning
B. Conditioning, memory
_____ 7. Personality
C. The psychology of law
_____ 8. Sensation and perception
D. Brain and nervous system
_____ 9. Biopsychology
E. Child psychology
_____ 10. Social psychology
F. Individual differences,
_____ 11. Comparative psychology
motivation
G. Animal behavior
H. Processing sensory
information
REFLECT
Critical Thinking
12. All sciences are interested in controlling the phenomena they study.
T or F?
Relate
At first, many students think that psychology is primarily about abnormal behavior and psychotherapy. Did you? How would you describe the
field now?
Answers: 1. scientific, behavior, mental 2. d 3. models 4. b 5. E 6. B 7. F
8. H 9. D 10. A 11. G 12. F Astronomy and archaeology are examples of
sciences that do not share psychology’s fourth goal.
•
•
•
•
Critical Thinking — Take It with
a Grain of Salt
Gateway Question: What is critical thinking?
How does critical thinking play a role in psychology? Most of us
would be skeptical when offered a “genuine” Rolex watch or
expensive designer sunglasses for just a few dollars on eBay. Likewise, most of us easily accept our ignorance of subatomic physics.
But because we deal with human behavior every day, we tend to
think that we already know what is true in psychology. All too
often, we are tempted to “buy” common-sense beliefs and even
outrageous claims about psychics “channeling” dead people, the
powers of “healing” crystals, “miraculous” herbal remedies, astrology, and so forth.
For these and many more reasons, learning to think critically is
one of the lasting benefits of a college education. Critical thinking refers to an ability to reflect on, evaluate, compare, analyze,
critique, and synthesize information. Critical thinkers are willing
to challenge conventional wisdom by asking the hard questions.
For example, everyone knows that women are more talkative than
men, right? Critical thinkers might immediately ask: “How do
we know that women talk more than men? Is there any empirical
evidence that supports this “wisdom”? (Be on the lookout later in
this chapter for some evidence concerning this belief.) What could
we do to find out for ourselves?
Thinking About Behavior
The heart of critical thinking is a willingness to actively reflect on
ideas. Critical thinkers evaluate ideas by analyzing the evidence
supporting their beliefs and probe for weaknesses in their reasoning. They question assumptions and look for alternate conclusions. True knowledge, they recognize, comes from constantly
revising our understanding of the world. They are not afraid to
admit they were wrong. As Susan Blackmore (2001) said when her
studies caused her to abandon some long-held beliefs, “Admitting
you are wrong is always hard — even though it’s a skill that every
psychologist has to learn.”
Critical thinking relies on the following basic principles (Elder,
2006; Kida, 2006):
1. Few “truths” transcend the need for empirical testing. While
religious beliefs and personal values may be held as matters
of faith, without supporting evidence, most other ideas can
be evaluated by applying the rules of logic, evidence, and the
scientific method.
2. Judging the quality of evidence is crucial. Imagine that you are
a juror in a courtroom, judging claims made by two battling
lawyers. To decide correctly, you can’t just weigh the amount
of evidence. You must also critically evaluate the quality of
the evidence. Then you can give greater weight to the most
credible facts.
3. Authority or claimed expertise does not automatically make an
idea true. Just because a teacher, guru, celebrity, or authority
Introduction to Psychology and Research Methods
17
To put these principles into action, here are some questions to
ask over and over again as you evaluate new information (Browne
& Keeley, 2007; Elder, 2006):
1. What claims are being made? What are their implications?
2. What tests (if any) of these claims has been made? What was
the nature and quality of the tests? Are they credible? Can
they be repeated?
3. How good is the evidence? (In general, scientific observations provide the highest-quality evidence.)
4. Who did the tests? How reliable and trustworthy were the
investigators? Do they have conflicts of interest? Do their
findings appear to be objective? Has any other independent
researcher duplicated the findings?
5. Finally, how much credibility can the claim be given? High,
medium, low, provisional?
A course in psychology naturally enriches thinking skills. In
this book, all upcoming chapters include Critical Thinking questions like the ones you have seen here. Take the time to tackle
these questions. The effort will sharpen your thinking abilities and
make learning more lively. For an immediate thinking challenge,
let’s take a critical look at several nonscientific systems that claim
to explain behavior.
Pseudopsychologies — Palms,
Planets, and Personality
Gateway Question: How does psychology differ from false
explanations of behavior?
A pseudopsychology (SUE-doe-psychology) is any unfounded
system that resembles psychology. Many pseudopsychologies give
the appearance of science but are actually false. (Pseudo means
“false.”) Pseudopsychologies change little over time because followers seek evidence that appears to confirm their beliefs and avoid evidence that contradicts their beliefs. Scientists, in contrast, actively
look for contradictions as a way to advance knowledge. They are
skeptical critics of their own theories (Schick & Vaughn, 2004).
Can you give some examples of false psychologies? One early pseudopsychology, known as phrenology, was popularized in the nine-
Bettmann/Corbis
is convinced or sincere doesn’t mean you should automatically believe them. It is unscientific and self-demeaning to
just take the word of an “expert” without asking, “What evidence convinced her or him? How good is it? Is there a better
explanation?”
4. Critical thinking requires an open mind. Be prepared to
consider daring departures and go wherever the evidence
leads. However, don’t become so “open-minded” that you
are simply gullible. As astronomer Carl Sagan once noted,
“It seems to me that what is called for is an exquisite balance
between two conflicting needs: the most skeptical scrutiny of
all hypotheses that are served up to us and at the same time a
great openness to new ideas” (Kida, 2006, p. 51).
Phrenology was an attempt to assess personality characteristics by examining
various areas of the skull. Phrenologists used charts such as the one shown here
as guides. Like other pseudopsychologists, phrenologists made no attempt to
empirically verify their concepts.
teenth century by Franz Gall, a German anatomy teacher. Phrenology claimed that personality traits are revealed by the shape of
the skull. Modern research has long since shown that bumps on
the head have nothing to do with talents or abilities. In fact, the
phrenologists were so far off that they listed the part of the brain
that controls hearing as a center for “combativeness”! Palmistry is a
similar false system that claims lines on the hand reveal personality
traits and predict the future. Despite the overwhelming evidence
against this, palmists can still be found separating the gullible
from their money in many cities.
At first glance, a pseudopsychology called graphology might seem
more reasonable. Some graphologists claim that personality traits
are revealed by handwriting. Based on such claims, some companies
use graphologists to select job candidates. This is troubling because
graphologists score close to zero on tests of accuracy in rating personality (Furnham, Chamorro-Premuzic, & Callahan, 2003). In
fact, graphologists do no better than untrained college students
in rating personality and job performance (Neter & Ben-Shakhar,
1989). Even a graphological society recently concluded that handwriting analysis should not be used to select people for jobs (Simner
& Goffin, 2003). (By the way, graphology’s failure at revealing personality should be separated from its value for detecting forgeries.)
Graphology might seem harmless enough. However, imagine
being denied a job because a graphologist didn’t like your handwriting. This false system has been used to determine who is hired,
given bank credit, or selected for juries. In these and similar situations, pseudopsychologies do, in fact, harm people.
Critical thinking An ability to reflect on, evaluate, compare, analyze,
critique, and synthesize information.
Pseudopsychology Any false and unscientific system of beliefs and
practices that is offered as an explanation of behavior.
18
CHAPTER 1
Uncritical Acceptance
Even daily horoscopes printed in newspapers can seem uncannily accurate. However, such perceptions are typically based on
uncritical acceptance (the tendency to believe positive or flattering descriptions of yourself ). Horoscopes are generally made
up of mostly flattering traits. Naturally, when your personality is
described in desirable terms, it is hard to deny that the description
has the “ring of truth.” How much acceptance would astrology
receive if a birth sign read like this:
Virgo: You are the logical type and hate disorder. Your nitpicking is unbearable to your friends. You are cold, unemotional, and usually fall asleep while
making love. Virgos make good doorstops.
If pseudopsychologies have no scientific basis, how do they survive
and why are they popular? There are several reasons, all of which
can be illustrated by a critique of astrology.
Problems in the Stars
Astrology is arguably the most popular pseudopsychology. Astrology holds that the positions of the stars and planets at the time of
one’s birth determine personality traits and affect behavior. Like
other pseudopsychologies, astrology has repeatedly been shown to
have no scientific validity. The objections to astrology are numerous and devastating (Kelly, 1999):
1. A study of more than 3,000 predictions by famous astrologers found that only a small percentage were fulfilled. These
“successful” predictions tended to be vague (“There will
be a tragedy somewhere in the east in the spring”) or easily
guessed from current events (Culver & Ianna, 1988).
2. If astrologers are asked to match people with their horoscopes,
they do no better than would be expected by chance. In one
famous test, astrologers could not even use horoscopes to distinguish murderers from law-abiding people (Gauquelin, 1970).
3. There is no connection between people’s astrological signs
and their intelligence or personality traits (Hartmann,
Reuter, & Nyborg, 2006). There is also no connection
between the “compatibility” of couples’ astrological signs and
their marriage and divorce rates or between astrological signs
and leadership, physical characteristics, or career choices
(Martens & Trachet, 1998).
4. Astrologers have failed to explain why the moment of birth
should be more important than, say, the moment of conception. (Perhaps it is because it is relatively easy to figure out
the moment of birth and much trickier and touchy to determine the moment of conception.) Besides, the zodiac has
shifted in the sky by one full constellation since astrology was
first set up. (In other words, if astrology calls you a Scorpio
you are really a Libra, and so forth.) However, most astrologers simply ignore this shift (Martens & Trachet, 1998).
In short, astrology doesn’t work.
Then why does astrology often seem to work? The following discussion explains why.
Positive Instances
Even when an astrological description contains a mixture of good
and bad traits it may seem accurate. To find out why, read the following personality description.
Your Personality Profile
You have a strong need for other people to like you and for them to admire
you. You have a tendency to be critical of yourself. You have a great deal of
unused energy which you have not turned to your advantage. While you
have some personality weaknesses, you are generally able to compensate
for them. Your sexual adjustment has presented some problems for you.
Disciplined and controlled on the outside, you tend to be worrisome and
insecure inside. At times you have serious doubts as to whether you have
made the right decision or done the right thing. You prefer a certain amount
of change and variety and become dissatisfied when hemmed in by restrictions and limitations. You pride yourself on being an independent thinker
and do not accept other opinions without satisfactory proof. You have
found it unwise to be too frank in revealing yourself to others. At times you
are extroverted, affable, sociable, while at other times you are introverted,
wary, and reserved. Some of your aspirations tend to be pretty unrealistic.*
Does this describe your personality? A psychologist read this
summary individually to college students who had taken a personality test. Only 5 students out of 79 felt that the description
was inaccurate. Another classic study found that people rated this
“personality profile” as more accurate than their actual horoscopes
(French et al., 1991).
Reread the description and you will see that it contains both sides
of several personality dimensions (“At times you are extroverted . . .
while at other times you are introverted”). Its apparent accuracy is
an illusion based on the fallacy of positive instances, in which we
remember or notice things that confirm our expectations and forget
the rest. The pseudopsychologies thrive on this effect. For example,
you can always find “Aquarius characteristics” in an Aquarius. If
you looked, however, you could also find “Gemini characteristics,”
“Scorpio characteristics,” or whatever. Perhaps this explains why, in
an ironic twist, 94% of those sent the full 10-page horoscope of a
famous mass murderer accepted it as their own (Gauquelin, 1970).
*Reprinted with permission of author and publisher from: R. E. Ulrich, T. J. Stachnik, and N. R.
Stainton, “Student acceptance of generalized personality interpretations,” Psychological Reports, 13,
1963, 831–834.
19
Introduction to Psychology and Research Methods
The Barnum Effect
Pseudopsychologies also take advantage of the Barnum effect,
which is a tendency to consider personal descriptions accurate if
they are stated in general terms (Kida, 2006). P. T. Barnum, the
famed circus showman, had a formula for success: “Always have a
little something for everybody.” Like the all-purpose personality
profile, palm readings, fortunes, horoscopes, and other products
of pseudopsychology are stated in such general terms that they
can hardly miss. There is always “a little something for everybody.”
To observe the Barnum effect, read all 12 of the daily horoscopes
found in newspapers for several days. You will find that predictions
for other signs fit events as well as those for your own sign do. Try
giving a friend the wrong horoscope sometime. Your friend may
still be quite impressed with the “accuracy” of the horoscope.
Astrology’s popularity shows that many people have difficulty
separating valid psychology from systems that seem valid but are
not. The goal of this discussion, then, has been to make you a more
critical observer of human behavior and to clarify what is, and what
is not, psychology. Here is what the “stars” say about your future:
Emphasis now on education and personal improvement. A learning experience of lasting value awaits you. Take care of scholastic responsibilities
before engaging in recreation. The word psychology figures prominently in
your future.
Pseudopsychologies may seem like no more than a nuisance,
but they can do harm. For instance, people seeking treatment for
psychological disorders may become the victims of self-appointed
“experts” who offer ineffective, pseudoscientific “therapies” (Kida,
2006; Lilienfeld et al., 2005). Valid psychological principles are
based on scientific observation and evidence, not fads, opinions,
or wishful thinking.
Non Sequitur © 1993. Reprinted by permission
of Universal Press Syndicate.
The fallacy of positive instances is also used by various “psychic mediums” who pretend to communicate
with the deceased friends and relatives of audience
members. An analysis shows that the number of “hits”
(correct statements) made by these fakes tends to be
very low. Nevertheless, many viewers are impressed
because of the natural tendency to remember apparent
hits and ignore misses. Of course, embarrassing misses
are often edited out before the shows appear on television (Nickell, 2001).
a silver lining.” With this in mind, you use your lover’s worrisome
absences as a chance to spend more time with your family. You
take comfort in this “silver lining” until a family member comments, “Where there’s smoke, there’s fire!” Much of what passes
for common sense is equally vague and inconsistent. Notice also
that most of these B.S. statements work best after the fact. (B.S.,
of course, stands for Before Science.)
Systematically recording facts and events is the heart of all sciences. To be scientific, our observations must be systematic, so that
they reveal something about behavior (Stanovich, 2007). To use
an earlier example, if you are interested in heat and aggression, you
will learn little by driving around and making haphazard observations of aggressive behavior. To be of value, your observations must
be planned and systematic.
The Scientific Method
The scientific method is a form of critical thinking based on careful collection of evidence, accurate description and measurement,
precise definition, controlled observation, and repeatable results
( Jackson, 2008). In its ideal form the scientific method has six
elements:
1.
2.
3.
4.
5.
6.
Making observations
Defining a problem
Proposing a hypothesis
Gathering evidence/testing the hypothesis
Publishing results
Theory building
Let’s take a closer look at some elements of the scientific
method. All the basic elements of the scientific method are found
in the example that follows.
Scientific Research — How
to Think Like a Psychologist
Gateway Question: How is the scientific method applied in
psychological research?
Suppose that your friend marries someone just like her. What
do people say? “Ah . . . birds of a feather flock together.” And
what do they say if she gets divorced soon after? “Well, she
should have known that opposites attract.” Let’s examine another
common-sense statement. It is frequently said that “every cloud has
Uncritical acceptance The tendency to believe generally positive or
flattering descriptions of oneself.
Fallacy of positive instances The tendency to remember or notice
information that fits one’s expectations while forgetting discrepancies.
Barnum effect The tendency to consider a personal description
accurate if it is stated in very general terms.
Scientific method A form of critical thinking based on careful
measurement and controlled observation.
20
CHAPTER 1
Conceptual Level
Hypothesized relationship
Concepts
Frustration
Aggression
Interrupted
finishing a
puzzle
Number of times
person insults
interrupter
Concrete Level
© Dan McCoy/Rainbow
Operational
definitions
Observed relationship
Figure 1.2 Operational definitions are used to link concepts with concrete
•observations.
Do you think the examples given are reasonable operational definitions of frustration and aggression? Operational definitions vary in how well they
represent concepts. For this reason, many different experiments may be necessary
to draw clear conclusions about hypothesized relationships in psychology.
Applying the scientific method to the study of behavior requires careful observation. Here, a psychologist videotapes a session in which a child’s thinking abilities are being tested.
Observation
Many people believe that women are more chatty than men. Is
there any truth to this belief ? University of Arizona psychologist
Mathias Mehl and his colleagues observed that the results of a few
published reports do seem to support this stereotype.
trated individual insults the person who prevented work on the
puzzle.” In other words, covert behaviors are operationally defined
in terms of overt behavior so they can be observed and studied
scientifically.
Gathering Evidence/Testing the Hypothesis
Defining a Problem
However, the researchers noticed that none of the studies had
actually recorded men’s and women’s normal conversations over
long periods. Thus, they defined their problem as, “How can we
record natural conversations without bothering people and perhaps biasing our observations?”
Proposing a Hypothesis
What exactly is a “hypothesis”? A hypothesis (hi-POTH-eh-sis) is a
tentative statement about, or explanation of, an event or relationship. In common terms, a hypothesis is a testable hunch or educated guess about behavior. For example, you might hypothesize
that “Frustration encourages aggression.” How could you test this
hypothesis? First you would have to decide how you are going to
frustrate people. (This part might be fun.) Then you will need to
find a way to measure whether or not they become more aggressive. (Not so much fun if you plan to be nearby.) Your observations would then provide evidence to confirm or disconfirm the
hypothesis.
Because we cannot see or touch frustration, we must define it
operationally. An operational definition states the exact procedures used to represent a concept. Operational definitions allow
unobservable ideas, such as covert behaviors, to be tested in realworld terms ( Figure 1.2). For example, since you can’t measure
frustration directly, you might define frustration as “interrupting
an adult before he or she can finish a puzzle and win an iPhone.”
And aggression might be defined as “the number of times a frus-
•
Now let’s return to the question of whether women talk more than
men do. To gather data, the researchers used an electronically activated recorder (EAR) to track people’s conversations. This device
recorded sounds for 30 seconds every 12.5 minutes. Participants
could not tell when they were being recorded, so they acted and
spoke normally. Researchers counted the number of words spoken
when the recorder was on and used that to estimate the total number of words spoken each day. On average, women spoke 16,215
words a day, with men close behind at 15,699. This difference is
too small to be meaningful, so we can conclude, as Mehl did, that
there is no evidence that women talk more than men (Mehl et al.,
2007).
Publishing Results
Scientific information must always be publicly available. That way,
other researchers can read about the results and make their own
observations if they doubt the study’s findings. If others are able
to replicate (repeat) the results of a study, those results become
more credible.
The results of psychological studies are usually published in
professional journals ( Table 1.1). That way, anyone willing to
make appropriate observations can see whether or not a claim
is true ( Jackson, 2008). In a scholarly article, Mehl and his
colleagues carefully describe the question they investigated, the
methods they used, and the results of their study on male and
female talkativeness. The article was published in the journal Science (Mehl et al., 2007).
•
Introduction to Psychology and Research Methods
Table 1.1
• Outline of a Research Report
• Abstract Research reports begin with a very brief summary of the study
and its findings. The abstract allows you to get an overview without
reading the entire article.
• Introduction The introduction describes the question to be investigated. It also provides background information by reviewing prior
studies on the same or related topics.
• Method This section tells how and why observations were made. It also
describes the specific procedures used to gather data. That way, other
researchers can repeat the study to see if they get the same results.
• Results The outcome of the investigation is presented. Data may be
graphed, summarized in tables, or statistically analyzed.
• Discussion The results of the study are discussed in relation to the
original question. Implications of the study are explored and further
studies may be proposed.
21
bridges
One of the major limitations of Freudian personality theory is
that many of its concepts are not testable or falsifiable. See
Chapter 12, page 402.
While Mehl and his colleagues did not present a theory of why
humans talk more or less, they did discuss how their findings might
affect such a theory. For instance, they pointed out that they only
studied university students, and that older men and women might
differ in how much they talk each day. Such findings invite others
to study talkativeness in other age groups and to propose theories
to explain any differences that might be observed.
Theory Building
What about theory building? In research, a theory acts as a map
of knowledge. Good theories summarize observations, explain
them, and guide further research ( Figure 1.3). Without theories
of forgetting, personality, stress, mental illness, and the like, psychologists would drown in a sea of disconnected facts (Stanovich,
2007).
•
Observation
Define problem
Propose hypothesis
Gather evidence
Test hypothesis
Reject hypothesis
Retain hypothesis
KNOWL E DG E B U I L DE R
Critical Thinking and the Scientific
Method in Psychology
RECITE
1. The fallacy of positive instances refers to graphology’s accepted
value for the detection of forgeries. T or F?
2. Personality descriptions provided by pseudopsychologies are stated
in general terms, which provide “a little something for everybody.”
This fact is the basis of the
a. palmist’s fallacy
b. uncritical acceptance pattern
c. fallacy of positive instances
d. Barnum effect
3. Most of psychology can rightfully be called common sense because
psychologists prefer informal observation to systematic observation.
T or F?
4. A psychologist does a study to see if exercising increases sense of
well-being. In the study he will be testing an
a. experimental hypothesis
b. operational definition
c. empirical definition
d. anthropomorphic theory
5. ____________ behaviors are operationally defined in terms of
____________ behavior
a. overt, covert
b. observable, overt
c. covert, overt
d. covert, abstract
Continued
Publish results
Theory building
Figure 1.3 Psychologists use the logic of science to answer questions about
•behavior.
Specific hypotheses can be tested in a variety of ways, including controlled experiments, naturalistic observation, correlational studies, clinical studies,
and the survey method. Psychologists revise their theories to reflect the evidence
they gather. New or revised theories then lead to new observations, problems, and
hypotheses.
Hypothesis The predicted outcome of an experiment or an educated
guess about the relationship between variables.
Operational definition Defining a scientific concept by stating the
specific actions or procedures used to measure it. For example, “hunger”
might be defined as “the number of hours of food deprivation.”
Theory A system of ideas designed to interrelate concepts and facts in a
way that summarizes existing data and predicts future observations.
CHAPTER 1
REFLECT
Critical Thinking
6. Can you think of some “common-sense” statements that contradict
each other?
7. Try constructing a few “Barnum statements,” personality statements
so general that virtually everyone will think they apply to themselves. Can you string them together to make a “Barnum personality
profile”? Can you adapt the same statements to construct a “Barnum
horoscope”?
8. Each New Year’s Day, phony “psychics” make predictions about
events that will occur during the coming year. The vast majority of
these predictions are wrong, but the practice continues each year.
Can you explain why?
Relate
It is nearly impossible to get through a day without encountering
people who believe in pseudopsychologies or who make unscientific or
unfounded statements. How stringently do you evaluate your own beliefs
and the claims made by others?
How might you scientifically test the old saw that you can’t teach an
old dog new tricks? Follow the steps of the scientific method to propose
a testable hypothesis and decide how you would gather evidence. (Well,
OK, you don’t have to publish your results.)
Answers: 1. F 2. d 3. F 4. a 5. c 6. There are many examples. Here are a
few more to add to the ones you thought of: “He (or she) who hesitates
is lost” versus “Haste makes waste.” “Never too old to learn” versus “You
can’t teach an old dog new tricks.” 7. The term “Barnum statement”
comes from Levy (2003), who offers the following examples: You are
afraid of being hurt. You are trying to find a balance between autonomy
and closeness. You don’t like being overly dependent. You just want to
be understood. 8. Because of the fallacy of positive instances, people
only remember predictions that seemed to come true and forget all the
errors. Incidentally, “predictions” that appear to be accurate are usually
easily deduced from current events or are stated in very general terms to
take advantage of the Barnum effect.
A Brief History of Psychology —
Psychology’s Family Album
Gateway Question: How did the field of psychology emerge?
As we noted previously, people have been informally observing
human behavior and philosophizing about it for thousands of
years. In contrast, psychology’s history as a science dates back only
about 130 years to Leipzig, Germany. There, Wilhelm Wundt
(VILL-helm Voont), the “father of psychology,” set up a laboratory in 1879 to study conscious experience.
What happens, he wondered, when we experience sensations,
images, and feelings? To find out, Wundt systematically observed
and measured stimuli of various kinds (lights, sounds, weights).
A stimulus is any physical energy that affects a person and evokes
a response (stimulus: singular; stimuli [STIM-you-lie]: plural).
Wundt then used introspection, or “looking inward,” to probe his
reactions to various stimuli. (Stop reading, close your eyes, carefully examine your thoughts, feelings, and sensations, and you will
be introspecting.)
Wilhelm Wundt, 1832–1920. Wundt is credited with
making psychology an independent science, separate from philosophy. Wundt’s original training was in medicine, but he became deeply
interested in psychology. In his laboratory,
Wundt investigated how sensations, images,
and feelings combine to make up personal
experience.
Hulton Archive/Getty Images
22
Over the years, Wundt studied vision, hearing, taste, touch,
memory, time perception, and many other topics. By insisting on
systematic observation and measurement, he asked some interesting questions and got psychology off to a good start (Schultz &
Schultz, 2008).
Structuralism
Wundt’s ideas were carried to the United States by Edward Titchener (TICH-in-er). Titchener called Wundt’s ideas structuralism
and tried to analyze the structure of mental life into basic “elements” or “building blocks.”
How could he do that? You can’t analyze experience like a chemical compound, can you? Perhaps not, but the structuralists tried,
mostly by using introspection. For instance, an observer might
heft an apple and decide that she had experienced the elements
“hue” (color), “roundness,” and “weight.” Another example of a
question that might have interested a structuralist is, What basic
tastes mix together to create complex flavors as different as broccoli, lime, bacon, and strawberry cheesecake?
Introspection proved to be a poor way to answer most questions (Benjafield, 2004). Why? Because no matter how systematic
the observations, the structuralists frequently disagreed. And when
they did, there was no way to settle differences. Think about it. If
you and a friend both introspect on your perceptions of an apple
and end up listing different basic elements, who would be right?
Despite such limitations, “looking inward” is still used as one
source of insight in studies of hypnosis, meditation, problem solving, moods, and many other topics.
Functionalism
American scholar William James broadened psychology to include
animal behavior, religious experience, abnormal behavior, and
other interesting topics. James’s brilliant first book, Principles of
Psychology (1890), helped establish the field as a separate discipline (Hergenhahn, 2005).
The term functionalism comes from James’s interest in how
the mind functions to help us adapt to the environment. James
regarded consciousness as an ever-changing stream or flow of
images and sensations — not a set of lifeless building blocks, as the
structuralists claimed.
The functionalists admired Charles Darwin, who deduced that
creatures evolve in ways that favor survival. According to Darwin’s
principle of natural selection, physical features that help animals
adapt to their environments are retained in evolution. Similarly,
the functionalists wanted to find out how the mind, perception,
habits, and emotions help us adapt and survive.
What effect did functionalism have on modern psychology? Functionalism brought the study of animals into psychology. It also
promoted educational psychology (the study of learning, teaching, classroom dynamics, and related topics). Learning makes us
more adaptable, so the functionalists tried to find ways to improve
education. For similar reasons, functionalism gave rise to industrial psychology, the study of people at work.
bridges
Today, educational psychology and industrial psychology remain
two major applied specialties. See Chapter 18 for more
information about applied psychology.
Behaviorism
Functionalism and structuralism were soon challenged by behaviorism, the study of observable behavior. Behaviorist John B.
Watson objected strongly to the study of the “mind” or “conscious
experience.” He believed that introspection is unscientific because
there is no way to settle disagreements between observers. Watson
realized that he could study the behavior of animals even though
he couldn’t ask them questions or know what they were thinking (Watson, 1913/1994). He simply observed the relationship
between stimuli (events in the environment) and an animal’s
responses (any muscular action, glandular activity, or other identifiable behavior). These observations were objective because they
did not involve introspecting on subjective experience. Why not,
he asked, apply the same objectivity to human behavior?
Watson soon adopted Russian physiologist Ivan Pavlov’s (eeVAHN PAV-lahv) concept of conditioning to explain most behavior. (A conditioned response is a learned reaction to a particular
stimulus.) Watson claimed, “Give me a dozen healthy infants,
well-formed, and my own special world to bring them up in and I’ll
23
John B. Watson, 1878–1958. Watson’s intense interest in observable behavior began with his doctoral studies in biology and neurology. Watson
became a psychology professor at Johns
Hopkins University in 1908 and advanced
his theory of behaviorism. He remained at
Johns Hopkins until 1920 when he left for a
career in the advertising industry!
guarantee to take any one at random and train him to become any
type of specialist I might select — doctor, lawyer, artist, merchantchief, and yes, beggarman and thief ” (Watson, 1913/1994).
Would most psychologists agree with Watson’s claim? No, today
it is regarded as an overstatement. Just the same, behaviorism
helped make psychology a natural science, rather than a branch of
philosophy (Benjafield, 2004).
Radical Behaviorism
The best-known behaviorist, B. F. Skinner (1904–1990), believed
that our actions are controlled by rewards and punishments. To
study learning, Skinner created his famous conditioning chamber,
or “Skinner box.” With it, he could present stimuli to animals and
record their responses.
bridges
See Chapter 7, pages 226–241, for more information about
operant conditioning.
Many of Skinner’s ideas about learning grew out of work with
rats and pigeons. Nevertheless, he believed that the same laws of
behavior apply to humans. As a “radical behaviorist,” Skinner also
believed that mental events, such as thinking, are not needed to
explain behavior (Schultz & Schultz, 2008).
Stimulus Any physical energy sensed by an organism.
Introspection To look within; to examine one’s own thoughts, feelings,
or sensations.
Structuralism The school of thought concerned with analyzing
sensations and personal experience into basic elements.
Functionalism The school of psychology concerned with how behavior
and mental abilities help people adapt to their environments.
Natural selection Darwin’s theory that evolution favors those plants
and animals best suited to their living conditions.
Behaviorism The school of psychology that emphasizes the study of
overt, observable behavior.
Response Any muscular action, glandular activity, or other identifiable
aspect of behavior.
Archives of the History of American Psychology, University of Akron
William James, 1842–1910. William James was
the son of philosopher Henry James, Sr., and the
brother of novelist Henry James. During his
long academic career, James taught anatomy,
physiology, psychology, and philosophy at
Harvard University. James believed strongly
that ideas should be judged in terms of their
practical consequences for human conduct.
Archives of the History of American Psychology, University of Akron
Introduction to Psychology and Research Methods
24
CHAPTER 1
Cognitive Behaviorism
Radical behaviorists have been criticized for ignoring the role
that thinking plays in our lives. One critic even charged that
Skinnerian psychology had “lost consciousness!” However, many
criticisms have been answered by cognitive behaviorism, a view
that combines cognition (thinking) and conditioning to explain
behavior (Zentall, 2002). As an example, let’s say you frequently
visit a particular website because it offers free streaming videos.
A behaviorist would say that you visit the site because you are
rewarded by the pleasure of watching interesting videos each time
you go there. A cognitive behaviorist would add that, in addition,
you expect to find good videos at the site. This is the cognitive part
of your behavior.
Behaviorists deserve credit for much of what we know about
learning, conditioning, and the proper use of reward and punishment. Behaviorism is also the source of behavior therapy, which
uses learning principles to change problem behaviors such as
overeating, unrealistic fears, or temper tantrums. (See Chapter 15,
pages 503–509, for more information.)
Gestalt Psychology
Imagine that you just played “Happy Birthday” on a low-pitched
tuba. Next, you play it on a high-pitched flute. The flute duplicates none of the tuba’s sounds. Yet we notice something interesting: The melody is still recognizable — as long as the relationship
between notes remains the same.
Now, what would happen if you played the notes of “Happy
Birthday” in the correct order, but at a rate of one per hour? What
would we have? Nothing! The separate notes would no longer
be a melody. Perceptually, the melody is somehow more than the
individual notes that define it.
It was observations like these that launched the Gestalt school of
thought. German psychologist Max Wertheimer (VERT-hi-mer)
was the first to advance the Gestalt viewpoint. It is inaccurate, he
said, to analyze psychological events into pieces, or “elements,” as
the structuralists did. Accordingly, Gestalt psychologists studied
thinking, learning, and perception as whole units, not by analyz-
Figure 1.4 The design you see here is entirely made up of broken circles.
•However,
as the Gestalt psychologists discovered, our perceptions have a powerful
tendency to form meaningful patterns. Because of this tendency, you will probably
see a triangle in this design, even though it is only an illusion. Your whole perceptual experience exceeds the sum of its parts.
Max Wertheimer, 1880–1941. Wertheimer first
proposed the Gestalt viewpoint to help explain
perceptual illusions. He later promoted Gestalt
psychology as a way to understand not only
perception, problem solving, thinking, and
social behavior, but also art, logic, philosophy, and politics.
ing experiences into parts. Their slogan
was, “The whole is greater than the sum
of its parts” ( Figure 1.4). In fact the German word Gestalt means “form, pattern, or whole.”
Like a melody, many experiences cannot be broken into smaller
units, as the Structuralists proposed. For this reason, studies of
perception and personality have been especially influenced by
the Gestalt viewpoint. Gestalt psychology also inspired a type of
psychotherapy.
•
bridges
If you are curious about what Gestalt therapy is like, look
ahead to Chapter 15, pages 501–502.
Psychoanalytic Psychology
As American psychology grew more scientific, an Austrian doctor
named Sigmund Freud was developing radically different ideas which
opened new horizons in art, literature, and history, as well as psychology (Jacobs, 2003). Freud believed that mental life is like an iceberg:
Only a small part is exposed to view. He called the area of the mind
that lies outside of personal awareness the unconscious. According
to Freud, our behavior is deeply influenced by unconscious thoughts,
Archives of the History of American Psychology, University of Akron
Skinner was convinced that a
“designed culture” based on positive
reinforcement could encourage desirable behavior. (Skinner opposed the use of
punishment because it doesn’t teach correct responses.) Too often,
he believed, misguided rewards lead to destructive actions that
create problems such as overpopulation, pollution, and war.
Yvonne Hemsey/Getty Images
B. F. Skinner, 1904–1990. Skinner studied simple
behaviors under carefully controlled conditions.
The “Skinner box” has been widely used to
study learning in simplified animal experiments. In addition to advancing psychology,
Skinner hoped that his radical brand of
behaviorism would improve human life.
Introduction to Psychology and Research Methods
Humanistic Psychology
Humanism is a view that focuses on subjective human experience.
Humanistic psychologists are interested in human potentials, ideals, and problems.
How is the humanistic approach different from others? Carl Rogers, Abraham Maslow, and other humanists rejected the Freudian idea that we are ruled by unconscious forces. They were also
uncomfortable with the behaviorist emphasis on conditioning.
Both views have a strong undercurrent of determinism (the idea
that behavior is determined by forces beyond our control). In contrast, the humanists stress free will, our ability to make voluntary
choices. Of course, past experiences do affect us. Nevertheless,
humanists believe that people can freely choose to live more creative, meaningful, and satisfying lives.
Humanists are interested in psychological needs for love, self-esteem,
belonging, self-expression, creativity,
and spirituality. Such needs, they believe,
are as important as our biological urges for food and water. For
example, newborn infants deprived of human love may die just as
surely as they would if deprived of food.
How scientific is the humanistic approach? Initially, humanists were less interested in treating psychology as a science. They
stressed subjective factors, such as one’s self-image, self-evaluation,
and frame of reference. (Self-image is your perception of your
own body, personality, and capabilities. Self-evaluation refers to
appraising yourself as good or bad. A frame of reference is a mental
perspective used to interpret events.) Today, humanists still seek to
understand how we perceive ourselves and experience the world.
However, most now do research to test their ideas, just as other
psychologists do (Schneider, Bugental, & Pierson, 2001).
Maslow’s concept of self-actualization is a key feature of
humanism. Self-actualization refers to developing one’s poten-
Cognitive behaviorism An approach that combines behavioral
principles with cognition (perception, thinking, anticipation) to explain
behavior.
Gestalt psychology A school of psychology emphasizing the study of
thinking, learning, and perception in whole units, not by analysis into
parts.
Unconscious Contents of the mind that are beyond awareness,
especially impulses and desires not directly known to a person.
Repression The unconscious process by which memories, thoughts, or
impulses are held out of awareness.
Psychoanalysis A Freudian approach to psychotherapy emphasizing
the exploration of unconscious conflicts.
Neo-Freudian A psychologist who accepts the broad features of
Freud’s theory but has revised the theory to fit his or her own concepts.
Psychodynamic theory Any theory of behavior that emphasizes
internal conflicts, motives, and unconscious forces.
Humanism An approach to psychology that focuses on human
experience, problems, potentials, and ideals.
Determinism The idea that all behavior has prior causes that would
completely explain one’s choices and actions if all such causes were
known.
Free will The idea that human beings are capable of freely making
choices or decisions.
Self-actualization The ongoing process of fully developing one’s
personal potential.
Bettmann/Corbis
impulses, and desires—especially those
concerning sex and aggression.
Freud theorized that many unconscious thoughts are repressed (held out of
awareness) because they are threatening. But sometimes, he said,
they are revealed by dreams, emotions, or slips of the tongue.
(“Freudian slips” are often humorous, as when a student who is
late for class says, “I’m sorry I couldn’t get here any later.”)
Freud believed that all thoughts, emotions, and actions are
determined. In other words, nothing is an accident: If we probe
deeply enough, we will find the causes of every thought or action.
Freud was also among the first to appreciate that childhood affects
adult personality (“The child is father to the man”). Most of all,
perhaps, Freud is known for creating psychoanalysis, the first
fully developed psychotherapy, or “talking cure.” Freudian psychotherapy explores unconscious conflicts and emotional problems.
(See Chapter 15, pages 498–499, for details.)
It wasn’t very long before some of Freud’s students began to
promote their own theories. Several who modified Freud’s ideas
became known as neo-Freudians (neo means “new” or “recent”).
Neo-Freudians accepted much of Freud’s theory but revised
parts of it. Many, for instance, placed less emphasis on sex and
aggression and more on social motives and relationships. Some
well-known neo-Freudians are Alfred Adler, Anna Freud (Freud’s
daughter), Karen Horney (HORN-eye), Carl Jung (yoong), Otto
Rank (rahnk), and Erik Erikson. Today, Freud’s ideas have been
altered so much that few strictly psychoanalytic psychologists are
left. However, his legacy is still evident in various psychodynamic
theories, which continue to emphasize internal motives, conflicts,
and unconscious forces (Gedo, 2002).
Abraham Maslow, 1908–1970. As a founder of
humanistic psychology, Maslow was interested in
studying people of exceptional mental health.
Such self-actualized people, he believed,
make full use of their talents and abilities.
Maslow offered his positive view of human
potential as an alternative to the schools of
behaviorism and psychoanalysis.
Hulton Archive/Getty Images
Sigmund Freud, 1856–1939. For more than 50 years,
Freud probed the unconscious mind. In doing so,
he altered modern views of human nature. His
early experimentation with a “talking cure”
for hysteria is regarded as the beginning of
psychoanalysis. Through psychoanalysis,
Freud added psychological treatment methods to psychiatry.
25
• The Early Development of Psychology
Perspective
Date
Notable Events
Experimental
psychology
1875
First psychology course offered by William
James
First American Ph.D. in psychology
awarded
Wilhelm Wundt opens first psychology
laboratory in Germany
First American psychology lab founded at
Johns Hopkins University
First American psychology textbook written by John Dewey
1878
1879
1883
1886
Structuralism
1898
Functionalism
1890
1892
Edward Titchener advances psychology
based on introspection
William James publishes Principles of
Psychology
American Psychological Association
founded
Psychodynamic
psychology
1895
1900
Sigmund Freud publishes first studies
Freud publishes The Interpretation of
Dreams
Behaviorism
1906
Ivan Pavlov reports his research on conditioned reflexes
John Watson presents behavioristic view
1913
Gestalt
psychology
1912
Max Wertheimer and others advance
Gestalt viewpoint
Humanistic
psychology
1942
Carl Rogers publishes Counseling and
Psychotherapy
Abraham Maslow publishes “A Theory of
Human Motivation”
1943
tial fully and becoming the best person possible. According to
humanists, everyone has this potential. Humanists seek ways to
help it emerge. Table 1.2 presents a summary of psychology’s
early development.
•
bridges
Behaviorism, Gestalt psychology, psychoanalytic theory,
and humanism have all given rise to various forms of
psychotherapy. See Chapter 15 for more information about
how psychological disorders are treated.
The Role of Women in Psychology’s Early Days
Were all the early psychologists men? Even though most of the
early psychologists were men, women have contributed to psychology from the beginning (Minton, 2000). By 1906, in the
United States about 1 psychologist in 10 was a woman. Who
were these “foremothers” of psychology? Three who became well
known are Mary Calkins, Christine Ladd-Franklin, and Margaret
Washburn.
Mary Calkins did valuable research on memory and was also
the first woman president of the American Psychological Asso-
Mary Calkins, 1863–1930.
Christine Ladd-Franklin,
1847–1930.
ciation, in 1905. Christine Ladd-Franklin
studied color vision. In 1906 she was
ranked among the 50 most important
psychologists in America. In 1908
Margaret Washburn published an
influential textbook on animal behavior, titled The Animal Mind.
The first woman to be awarded
a Ph.D. in psychology was Margaret
Washburn, in 1894. Over the next 15
years many more women followed her
pioneering lead. Today, more than half
the members of the American Psychologi- Margaret Washburn,
1871–1939.
cal Association are women, two out of three
graduate students in psychology are women, and in recent
years nearly 75 percent of all college graduates with a major in
psychology have been women. Clearly, psychology has become
fully open to both men and women (Hyde, 2004).
Psychology Today — Three
Complementary Perspectives on Behavior
Gateway Question: What are the contemporary perspectives in
psychology?
At one time, loyalty to each school of thought was fierce, and
clashes were common. Now, some early systems, such as structuralism, have disappeared entirely while new ones have gained
prominence. Also, viewpoints such as functionalism and Gestalt
psychology have blended into newer, broader perspectives. Certainly, loyalties and specialties still exist. But today, many psychologists are eclectic (ek-LEK-tik), because they realize that a single
perspective is unlikely to fully explain complex human behavior.
As a result, psychologists commonly draw insight from a variety of
perspectives, with insights from one often complementing insights
from the other. The three broad views that shape modern psychology are the biological, psychological, and sociocultural perspectives
( Table 1.3).
•
Archives of the History of American Psychology, University
of Akron
Table 1.2
Archives of the History of American Psychology, University
of Akron
CHAPTER 1
Archives of the History of American Psychology, University
of Akron
26
Introduction to Psychology and Research Methods
Table 1.3
27
• Contemporary Ways to Look at Behavior
Biological Perspective
Biopsychological View
Key Idea: Human and animal behavior is the result of internal physical, chemical, and biological processes.
Seeks to explain behavior through activity of the brain and nervous system, physiology, genetics, the endocrine system, and biochemistry; neutral, reductionistic, mechanistic view of human nature.
Evolutionary View
Key Idea: Human and animal behavior is the result of the process of evolution.
Seeks to explain behavior through evolutionary principles based on natural selection; neutral, reductionistic, mechanistic view of
human nature.
S
R
INPUT
Processing
OUTPUT
CONSCIOUS
UNCONSCIOUS
Selfimage
Self
Selfevaluation
Social
Self
Psychological Perspective
Behavioristic View
Key Idea: Behavior is shaped and controlled by one’s environment.
Emphasizes the study of observable behavior and the effects of learning; stresses the influence of external rewards and punishments;
neutral, scientific, somewhat mechanistic view of human nature.
Cognitive View
Key Idea: Much human behavior can be understood in terms of the mental processing of information.
Concerned with thinking, knowing, perception, understanding, memory, decision making, and judgment; explains behavior in terms of
information processing; neutral, somewhat computer-like view of human nature.
Psychodynamic View
Key Idea: Behavior is directed by forces within one’s personality that are often hidden or unconscious.
Emphasizes internal impulses, desires, and conflicts — especially those that are unconscious; views behavior as the result of clashing
forces within personality; somewhat negative, pessimistic view of human nature.
Humanistic View
Key Idea: Behavior is guided by one’s self-image, by subjective perceptions of the world, and by needs for personal growth.
Focuses on subjective, conscious experience, human problems, potentials, and ideals; emphasizes self-image and self-actualization to
explain behavior; positive, philosophical view of human nature.
Sociocultural Perspective
Sociocultural View
Key Idea: Behavior is influenced by one’s social and cultural context.
Emphasizes that behavior is related to the social and cultural environment within which a person is born, grows up, and lives from day to
day; neutral, interactionist view of human nature.
Cultural
The Biological Perspective
The biological perspective seeks to explain our behavior in terms
of biological principles such as brain processes, evolution, and
genetics. By using new techniques, biopsychologists are producing
exciting insights about how the brain relates to thinking, feelings,
perception, abnormal behavior, and other topics. Biopsychologists
and others who study the brain and nervous system, such as biologists and biochemists, are part of the broader field of neuroscience.
As mentioned earlier, evolutionary psychologists look at how human
evolution and genetics might explain our current behavior.
acknowledge that mental processes underlie much of our behavior.
Cognitive psychology has gained greater prominence in recent
years as researchers have devised ways to objectively study covert
behaviors, such as thinking, memory, language, perception, problem solving, consciousness, and creativity. Cognitive psychologists
and other researchers interested in cognition, such as computer
scientists and linguists, form the broader field of cognitive science.
With a renewed interest in thinking, it can be said that psychology
has finally “regained consciousness” (Robins, Gosling, & Craik,
1998).
The Psychological Perspective
The psychological perspective takes the view that behavior is
shaped by psychological processes within each person. Although
it continues to emphasize objective observation, just as the early
behaviorists did, the psychological perspective now includes cognitive behaviorism and cognitive psychology. These perspectives
Biological perspective The attempt to explain behavior in terms of
underlying biological principles.
Psychological perspective The traditional view that behavior is
shaped by psychological processes occurring at the level of the
individual.
28
CHAPTER 1
Patrick Giardino/Corbis
Freudian psychoanalysis continues to evolve into the broader
psychodynamic view. Although many of Freud’s ideas have been
challenged, psychodynamic psychologists continue to trace human
behavior to unconscious processes. They also seek to develop
therapies to help people lead happier, fuller lives. Humanistic
psychologists do, too, although they stress subjective, conscious
experience and the positive side of human nature, rather than
unconscious processes.
Positive Psychology
Psychologists have always paid attention to the negative side of
human behavior. This is easy to understand because of the pressing
need to solve human problems. However, inspired by the humanists, more and more psychologists have recently begun to ask,
What do we know about love, happiness, creativity, well-being,
self-confidence, and achievement? Together, such topics make up
positive psychology, the study of human strengths, virtues, and
optimal behavior (Compton, 2005; Seligman & Csikszentmihalyi, 2000). Many topics from positive psychology can be found in
this book. Ideally, they will help make your own life more positive
and fulfilling (Simonton & Baumeister, 2005).
The Sociocultural Perspective
As you can see, it is helpful to view human behavior from more
than one perspective. This is also true in another sense. The sociocultural perspective stresses the impact that social and cultural
contexts have on our behavior. We are rapidly becoming a multicultural society, made up of people from many different nations.
How has this affected psychology? Let us introduce you to Jerry,
who is Japanese American and is married to an Irish-Catholic
American. Here is what Jerry, his wife, and their children did one
New Year’s Day:
We woke up in the morning and went to Mass at St. Brigid’s, which has a
black gospel choir. . . . Then we went to the Japanese-American Community
Center for the Oshogatsu New Year’s program and saw Buddhist archers
shoot arrows to ward off evil spirits for the year. Next, we ate traditional rice
cakes as part of the New Year’s service and listened to a young JapaneseAmerican storyteller. On the way home, we stopped in Chinatown and after
that we ate Mexican food at a taco stand. (Njeri, 1991)
Jerry and his family reflect a new social reality: Cultural diversity
is becoming the norm. More than 100 million Americans are now
African American, Hispanic, Asian American, Native American,
or Pacific Islander (United States Bureau of Census, 2007). In
some large cities “minority” groups are already the majority.
In the past, psychology was based mostly on the cultures of
North America and Europe. Now, we must ask, do the principles
of Western psychology apply to people in all cultures? Are some
psychological concepts invalid in other cultures? Are any universal? As psychologists have probed such questions, one thing has
become clear: Most of what we think, feel, and do is influenced in
one way or another by the social and cultural worlds in which we
live (Lehman, Chiu, & Schaller, 2004).
To fully understand human behavior, personal differences based on age, race,
culture, ethnicity, gender, and sexual orientation must be taken into account.
Cultural Relativity
Imagine that you are a psychologist. Your client, Linda, who is a
Native American, tells you that spirits live in the trees near her
home. Is Linda suffering from a delusion? Is she abnormal? Obviously, you will misjudge Linda’s mental health if you fail to take
her cultural beliefs into account. Cultural relativity (the idea
that behavior must be judged relative to the values of the culture
in which it occurs) can greatly affect the diagnosis and treatment
of mental disorders (Draguns, Gielen, & Fish, 2004). Cases like
Linda’s teach us to be wary of using narrow standards when judging others or comparing groups.
bridges
Psychotherapy can be less effective if a therapist and client
come from different cultures. See Chapter 15, page 517, for a
discussion of the impact of culture on therapy.
A Broader View of Diversity
In addition to cultural differences, age, ethnicity, gender, religion,
disability, and sexual orientation all affect the social norms that
guide behavior. Social norms are rules that define acceptable and
expected behavior for members of various groups. All too often,
the unstated standard for judging what is “average,” “normal,” or
“correct” has been the behavior of white, middle-class males (Reid,
2002). To fully understand human behavior, psychologists need
to know how people differ, as well as the ways in which we are all
alike. To be effective, psychologists must be sensitive to people
who are ethnically and culturally different from themselves (APA,
2003). For the same reason, an appreciation of human diversity
can enrich your life, as well as your understanding of psychology
(Denmark, Rabinowitz, & Sechzer, 2005).
In a moment we will further explore what psychologists do.
First, here are some questions to enhance your learning:
Introduction to Psychology and Research Methods
K N O W L E D GE B U I L D E R
History and Contemporary Perspectives
RECITE
Match:
_____ 1.
_____ 2.
_____ 3.
_____ 4.
_____ 5.
_____ 6.
_____ 7.
_____ 8.
_____ 9.
_____ 10.
_____ 11.
Philosophy
Wundt
Structuralism
Functionalism
Behaviorism
Gestalt
Psychodynamic
Humanistic
Cognitive
Washburn
Biopsychology
A. Against analysis; studied whole
experiences
B. “Mental chemistry” and introspection
C. Emphasizes self-actualization and
personal growth
D. Interested in unconscious causes of
behavior
E. Interested in how the mind aids
survival
F. First woman Ph.D. in psychology
G. Studied stimuli and responses,
conditioning
H. Part of psychology’s “long past”
I. Concerned with thinking, language,
problem solving
J. Used introspection and careful
measurement
K. Relates behavior to the brain,
physiology, and genetics
L. Also known as engineering
psychology
12. Who among the following was not a historic woman psychologist?
a. Calkins
b. Ladd-Franklin
c. Washburn
d. Watson
13. A psychotherapist is working with a person from an ethnic group
other than her own. She should be aware of how cultural relativity
and _____________________ affect behavior.
a. the anthropomorphic error
b. operational definitions
c. biased sampling
d. social norms
29
Psychologists — Guaranteed
Not to Shrink
Gateway Question: What are the major specialties in psychology?
Psychologists are all shrinks, right? Nope. “Shrinks” (a slang term
derived from “head shrinkers”) are psychiatrists, a different type of
mental health professional. A psychologist is highly trained in the
methods, knowledge, and theories of psychology. Psychologists
usually have a master’s degree or a doctorate. These degrees typically require several years of postgraduate training.
Psychologists are often inaccurately portrayed in the media.
Some films have featured psychologists who are more disturbed
than their patients (such as Jack Nicholson’s character in Anger
Management) or psychologists who are bumbling buffoons (such
as Billy Crystal’s character in Analyze This). In the comedy Prime
REFLECT
Relate
Which school of thought most closely matches your own view of behavior? Do you think any of the early schools offers a complete explanation
of why we behave as we do? What about the three broad contemporary
perspectives? Can you explain why so many psychologists are eclectic?
A group of psychologists were asked to answer this question: “Why
did the chicken cross the road?” Their answers are listed next. Can you
identify their theoretical orientations?
The chicken had been rewarded for crossing road in the past.
The chicken had an unconscious wish to become a pancake.
The chicken was trying to solve the problem of how to reach the
other side of the road.
The chicken felt a need to explore new possibilities as a way to actualize its potentials.
The chicken’s motor cortex was activated by messages from its hypothalamus.
© Mike Baldwin/CartoonStock
Critical Thinking
14. Modern sciences such as psychology are built on observations that
can be verified by two or more independent observers. Did structuralism meet this standard? Why or why not?
Positive psychology The study of human strengths, virtues, and
effective functioning.
Sociocultural perspective The focus on the importance of social and
cultural contexts in influencing the behavior of individuals.
Cultural relativity The idea that behavior must be judged relative to
the values of the culture in which it occurs.
Social norms Rules that define acceptable and expected behavior for
members of a group.
Psychologist A person highly trained in the methods, factual
knowledge, and theories of psychology.
Answers: 1. H 2. J 3. B 4. E 5. G 6. A 7. D 8. C 9. I 10. F 11. K 12. d 13. d
14. No, it did not. The downfall of structuralism was that each observer
examined the contents of his or her own mind, which is something that
no other person can observe.
30
CHAPTER 1
a therapist listens to a patient describe intimate details of her
relationship with a man but fails to tell the patient that the man
is her son. Such characters may be dramatic and entertaining, but
they seriously distort public perceptions of responsible and hardworking psychologists (Schultz, 2004). Real psychologists follow
an ethical code that stresses respect for people’s privacy, dignity,
confidentiality, and welfare (APA, 2002).
Even without media distortions, misconceptions about psychologists are common. For instance, most psychologists are
not therapists in private practice. Instead, they are employed by
schools, businesses, and social agencies. Likewise, only 16 percent
work in clinics or hospitals. Contrary to common belief, clinical
psychology is not the only specialty in the field. Only a little over
half of all psychologists study mental disorders or do therapy.
Others may teach, do research, give psychological tests, or serve as
consultants to business, industry, government, or the military.
Table 1.4
One perception of psychologists is accurate: Most do help people
in one way or another. Psychologists interested in emotional problems specialize in clinical or counseling psychology ( Table 1.4).
Clinical psychologists treat psychological problems or do research
on therapies and mental disorders. In contrast, counseling psychologists tend to treat milder problems, such as troubles at work or
school. However, such differences are fading, and many counseling
psychologists now work full time as therapists.
To enter the profession of psychology, it is best to have a doctorate (Ph.D., Psy.D., or Ed.D.). Most clinical psychologists have a
Ph.D. degree and follow a scientist-practitioner model. That is, they
are trained to do either research or therapy. Many do both. Other
clinicians earn the Psy.D. (Doctor of Psychology) degree, which
emphasizes therapy skills rather than research (Peterson, 2001).
Have you ever wondered what it takes to become a psychologist? See “Is a Career in Psychology Right for You?”
•
• Kinds of Psychologists and What They Do
Specialty
Typical Activities
Biopsychology
B*
Does research on the brain, nervous system, and other physical origins of behavior
Clinical
A
Does psychotherapy; investigates clinical problems; develops methods of treatment
Cognitive
B
Studies human thinking and information processing abilities
Community
A
Promotes community-wide mental health through research, prevention, education, and consultation
Comparative
B
Studies and compares the behavior of different species, especially animals
Consumer
A
Researches packaging, advertising, marketing methods, and characteristics of consumers
Counseling
A
Does psychotherapy and personal counseling; researches emotional disturbances and counseling methods
Cultural
B
Studies the ways in which culture, subculture, and ethnic group membership affect behavior
Developmental
A, B
Conducts research on infant, child, adolescent, and adult development; does clinical work with disturbed children; acts as
consultant to parents and schools
Educational
A
Investigates classroom dynamics, teaching styles, and learning; develops educational tests, evaluates educational programs
Engineering
A
Does applied research on the design of machinery, computers, airlines, automobiles, and so on, for business, industry, and
the military
Environmental
A, B
Studies the effects of urban noise, crowding, attitudes toward the environment, and human use of space; acts as a consultant on environmental issues
Forensic
A
Studies problems of crime and crime prevention, rehabilitation programs, prisons, courtroom dynamics; selects candidates
for police work
Gender
B
Does research on differences between males and females, the acquisition of gender identity, and the role of gender
throughout life
Health
A, B
Studies the relationship between behavior and health; uses psychological principles to promote health and prevent illness
Industrialorganizational
A
Selects job applicants, does skills analysis, evaluates on-the-job training, improves work environments and human relations
in organizations and work settings
Learning
B
Studies how and why learning occurs; develops theories of learning
Medical
A
Applies psychology to manage medical problems, such as the emotional impact of illness, self-screening for cancer, compliance in taking medicine
Personality
B
Studies personality traits and dynamics; develops theories of personality and tests for assessing personality traits
School
A
Does psychological testing, referrals, emotional and vocational counseling of students; detects and treats learning disabilities; improves classroom learning
Sensation and
perception
B
Studies the sense organs and the process of perception; investigates the mechanisms of sensation and develops theories
about how perception occurs
Social
B
Investigates human social behavior, including attitudes, conformity, persuasion, prejudice, friendship, aggression, helping,
and so forth
*Research in this area is typically applied (A), basic (B), or both (A, B).
Introduction to Psychology and Research Methods
31
D ISCOVERI N G P S Y CH OL O G Y
Is a Career in Psychology Right for You?
As you read this book we encourage you to
frequently reflect on new ideas by relating
them to your own life to better understand
and remember them. Discovering Psychology
boxes like this one are designed to help you
be more reflective about how psychology
relates to your own life. Answer the following questions to explore whether you would
enjoy becoming a psychologist:
1. I have a strong interest in human behavior. True or False?
2. I am good at recognizing patterns,
evaluating evidence, and drawing conclusions. True or False?
3. I am emotionally stable. True or False?
4. I have good communication skills. True
or False?
5. I find theories and ideas challenging and
stimulating. True or False?
6. My friends regard me as especially sensitive to the feelings of others. True or
False?
7. I enjoy planning and carrying out complex projects and activities. True or False?
8. Programs and popular books about psychology interest me. True or False?
9. I enjoy working with other people. True
or False?
10. Clear thinking, objectivity, and keen
observation appeal to me. True or False?
If you answered “True” to most of these questions, a career in psychology might be a good
choice. And remember that many psychology
majors also succeed in occupations such as
management, public affairs, social services,
business, sales, and education.
Other Mental Health Professionals
The Profession of Psychology
Clinical psychologists are not the only people who work in the
field of mental health. Often they coordinate their efforts with
other specially trained professionals. What are the differences
among psychologists, psychiatrists, psychoanalysts, counselors,
and other mental health professionals? Certainly, they’re not all
“shrinks.” Each has a specific blend of training and skills.
A psychiatrist is a medical doctor who treats mental disorders,
usually by doing psychotherapy. Psychiatrists can also prescribe
drugs, which is something psychologists usually cannot do. However, this is changing. Psychologists in New Mexico and Louisiana can now legally prescribe drugs. It will be interesting to see
whether other states grant similar privileges (Munsey, 2006).
To be a psychoanalyst, you must have a moustache and goatee,
spectacles, a German accent, and a well-padded couch — or so
the media stereotype goes. Actually, to become a psychoanalyst
you must have an M.D. or Ph.D. degree plus further training in
Freudian psychoanalysis. In other words, either a physician or a
psychologist may become an analyst by learning a specific type of
psychotherapy.
In many states, counselors also do mental health work. A
counselor is an adviser who helps solve problems with marriage,
career, school, work, or the like. To be a licensed counselor (such
as a marriage and family counselor, a child counselor, or a school
counselor) typically requires a master’s degree plus 1 or 2 years of
full-time supervised counseling experience. Counselors learn practical helping skills and do not treat serious mental disorders.
Psychiatric social workers play an important role in many
mental health programs, where they apply social science principles
to help patients in clinics and hospitals. Most hold an M.S.W.
(Master of Social Work) degree. Often, they assist psychologists
and psychiatrists as part of a team. Their typical duties include
evaluating patients and families; conducting group therapy; or
visiting a patient’s home, school, or job to alleviate problems.
Does a person have to have a license to practice psychology? At one
time it was possible in many states for anyone to “hang out a
shingle” as a “psychologist.” Now psychologists must meet rigorous educational and legal requirements. To work as a clinical or
counseling psychologist you must have a license issued by a state
examining board. However, the law does not prevent you from
calling yourself anything else you choose — therapist, rebirther,
primal feeling facilitator, cosmic aura balancer, or Rolfer — or
from selling your “services” to anyone willing to pay. Beware of
people with self-proclaimed titles. Even if their intentions are
honorable, they may have little training. A licensed psychologist
who chooses to use a particular type of therapy is not the same as
someone “trained” solely in that technique.
Ethics
Most psychologists take pride in following a professional code that
stresses (1) high levels of competence, integrity, and responsibility;
(2) respect for people’s rights to privacy, dignity, confidentiality,
Clinical psychologist A psychologist who specializes in the treatment
of psychological and behavioral disturbances or who does research on
such disturbances.
Counseling psychologist A psychologist who specializes in the
treatment of milder emotional and behavioral disturbances.
Psychiatrist A medical doctor with additional training in the diagnosis
and treatment of mental and emotional disorders.
Psychoanalyst A mental health professional (usually a medical doctor)
trained to practice psychoanalysis.
Counselor A mental health professional who specializes in helping
people with problems not involving serious mental disorder; for
example, marriage counselors, career counselors, or school counselors.
Psychiatric social worker A mental health professional trained to
apply social science principles to help patients in clinics and hospitals.
32
CHAPTER 1
and personal freedom; and, above all, (3) protection of the client’s
welfare. Psychologists are also expected to use their knowledge to
contribute to society. Many do volunteer work in the communities
in which they live (Barnett et al., 2007; APA, 2002).
Specialties in Psychology
Do all psychologists do therapy and treat abnormal behavior? No.
About 58 percent are clinical and counseling psychologists. The
rest are found in other specialties. At present, the American Psychological Association (APA) consists of more than 50 divisions,
each reflecting special skills or areas of interest. Some of the major
specialties are listed in Table 1.4. (Also see Figure 1.5.) Nearly
30 percent of all psychologists are employed full time at colleges
•
•
or universities, where they teach and do research, consulting, or
therapy. Some do basic research, in which they seek knowledge for
its own sake. For example, a psychologist might study memory
simply to understand how it works. Others do applied research
to solve immediate practical problems, such as finding ways to
improve athletic performance. Some do both types of research.
In a moment we’ll take a closer look at how research is done.
Before that, here’s a chance to do a little research on how much
you’ve learned:
KNOWL E DG E B U I L DE R
Psychologists and Their Specialties
RECITE
(a) Specialties in Psychology
48% Clinical
11% Counseling
18% Other
5% Experimental and
other research areas
1% Health
2% Educational
4% School
4% Industrial/organizational
3% Developmental 4% Social and personality
1. Which of the following is a medical doctor?
a. a psychologist
b. a psychiatrist
c. a psychotherapist
d. a counselor
2. A psychologist who specializes in treating human emotional difficulties is called a ____________________ psychologist.
3. Roughly 40 percent of psychologists specialize in counseling psychology. T or F?
4. Who among the following would most likely be involved in the
detection of learning disabilities?
a. a consumer psychologist
b. a forensic psychologist
c. an experimental psychologist
d. a school psychologist
REFLECT
34% Private practice
28% Colleges
and universities
14% Hospital/clinic
8% Other
Relate
Which specialty in psychology is most interesting to you? What is it about
that specialty that most attracts you?
Answers: 1. b 2. clinical or counseling 3. F 4. d 5. Because practitioners
benefit from basic psychological research in the same way that physicians benefit from basic research in biology. Discoveries in basic science
form the knowledge base that leads to useful applications.
(b) Where Psychologists Work
Critical Thinking
5. If most psychologists work in applied settings, why is basic research
still of great importance?
4% Schools
6% Human services
6% Business,
industry, government
(c) What Psychologists Do (Primary Activity)
50% Mental health
services
9% Other
4% Applied psychology
10% Research
18% Education and
educational services
9% Management/administration
• Figure 1.5 Specialties in psychology (APA, 2005). Percentages are approximate. (b) Where psychologists work (APA, 2000). (c) This chart shows the main activi(a)
ties psychologists engage in at work (APA, 2000). Any particular psychologist might
do several of these activities during a work week. As you can see, most psychologists specialize in applied areas and work in applied settings.
The Psychology Experiment — Where
Cause Meets Effect
Gateway Question: How is an experiment performed?
To get beyond description and fully understand behavior, psychologists must to be able explain why we act the way we do. To
discover the causes of behavior, we must usually conduct an experiment. An experiment is a formal trial undertaken to confirm or
disconfirm a hypothesis about the causes of behavior (although
causes are sometimes revealed by naturalistic observation or correlations). Experiments allow psychologists to carefully control
conditions and bring cause-and-effect relationships into sharp
focus. Hence, they are generally accepted as the most powerful
Introduction to Psychology and Research Methods
scientific research tool. To perform an experiment you would do
the following:
1. Directly vary a condition you think might affect behavior.
2. Create two or more groups of subjects. These groups should
be alike in all ways except the condition you are varying.
3. Record whether varying the condition has any effect on
behavior.
Suppose you want to find out if using cell phones while driving
a car affects the likelihood of having an accident. First, you would
form two groups. Then you could give the members of one group
a test of driving ability while they are using a cell phone. The second group would take the same test without using a cell phone. By
comparing average driving ability scores for the two groups, you
could tell if cell phone use affects driving ability.
As you can see, the simplest psychological experiment is based
on two groups of experimental subjects (animals or people whose
behavior is investigated; human subjects are also called participants). One group is called the experimental group; the other
becomes the control group. The control group and the experimental group are treated exactly alike except for the condition
you intentionally vary. This condition is called the independent
variable.
Variables and Groups
A variable is any condition that can change and that might affect
the outcome of the experiment. Identifying causes and effects in
an experiment involves three types of variables:
1. Independent variables are conditions altered or varied
by the experimenter, who sets their size, amount, or value.
Independent variables are suspected causes for differences in
behavior.
2. Dependent variables measure the results of the experiment.
That is, they reveal the effects that independent variables have
on behavior. Such effects are often revealed by measures of
performance, such as test scores.
3. Extraneous variables are conditions that a researcher wishes
to prevent from affecting the outcome of the experiment.
We can apply these terms to our cell phone/driving experiment
in this way: Cell phone use is the independent variable — we want
to know if cell phone use affects driving ability. Driving ability
(defined by scores achieved on a test of driving ability) is the
dependent variable — we want to know if the ability to drive well
depends on whether a person is using a cell phone. All other variables that could affect driving ability are extraneous. Examples of
extraneous variables are the number of hours slept the night before
the test, driving experience, or familiarity with the car used in the
experiment. (You might be interested to know that people using
cell phones drive no better than people who are legally drunk
[Strayer, Drews, & Crouch, 2006].)
As you can see, an experimental group consists of participants
exposed to the independent variable (cell phone use in the preced-
33
ing example). Members of the control group are exposed to all
conditions except the independent variable.
Let’s examine another simple experiment. Suppose you notice
that you seem to study better while listening to your iPod. This
suggests the hypothesis that music improves learning. We could
test this idea by forming an experimental group that studies with
music. A control group would study without music. Then we
could compare their scores on a test.
Is a control group really needed? Can’t people just study while listening to their iPods to see if they do better? Better than what? The
control group provides a point of reference for comparison with
the scores in the experimental group. Without a control group it
would be impossible to tell if music had any effect on learning. If
the average test score of the experimental group is higher than the
average of the control group, we can conclude that music improves
learning. If there is no difference, it’s obvious that the independent
variable had no effect on learning.
In this experiment, the amount learned (indicated by scores on
the test) is the dependent variable. We are asking, Does the independent variable affect the dependent variable? (Does music affect
or influence learning?)
Experimental Control
How do we know that the people in one group aren’t more intelligent
than those in the other group? It’s true that personal differences
might affect the experiment. However, they can be controlled
by randomly assigning people to groups. Random assignment
means that a participant has an equal chance of being in either the
experimental group or the control group. Randomization evenly
balances personal differences in the two groups. In our musical
experiment, this could be done by simply flipping a coin for each
participant: Heads, and the participant is in the experimental
Experiment A formal trial undertaken to confirm or disconfirm a
hypothesis about cause and effect.
Experimental subjects Humans (also referred to as participants) or
animals whose behavior is investigated in an experiment.
Variable Any condition that changes or can be made to change; a
measure, event, or state that may vary.
Independent variable In an experiment, the condition being
investigated as a possible cause of some change in behavior. The values
that this variable takes are chosen by the experimenter.
Dependent variable In an experiment, the condition (usually a
behavior) that is affected by the independent variable.
Extraneous variables Conditions or factors excluded from influencing
the outcome of an experiment.
Experimental group In a controlled experiment, the group of subjects
exposed to the independent variable or experimental condition.
Control group In a controlled experiment, the group of subjects
exposed to all experimental conditions or variables except the
independent variable.
Random assignment The use of chance (for example, flipping a coin)
to assign subjects to experimental and control groups.
34
CHAPTER 1
C R IT ICAL T H I N KI N G
That’s Interesting, but Is It Ethical?
In one classic study, participants were
ordered to give what they thought were
painful electric shocks to another person (no
shocks were actually given) (Milgram, 1963).
Believing that they had hurt someone, many
people left the experiment shaken and upset.
A few suffered guilt and distress for some
time afterward.
bridges
Stanley Milgram undertook
his infamous studies to better
understand just how willing people
are to obey an authority. See
Chapter 16, pages 547–549.
Such experiments raise serious ethical
questions about behavioral research. Did
the information gained justify the emotional costs? Was deception really necessary? As a reply to such questions, American
Psychological Association guidelines state
that “Psychologists must carry out investigations with respect for the people who participate and with concern for their dignity
and welfare.” Similar guidelines apply to animals, where investigators are expected to
“ensure the welfare of animals and treat them
humanely” (APA, 2002) ( Table 1.5).
To assure this, most university psychology departments have ethics committees
that oversee research. Nevertheless, no easy
answers exist for the ethical questions raised
by psychology, and debate about specific
experiments is likely to continue.
•
Possible
subjects
Random assignment
controls for subject
differences
Control
group
Experimental
group
Study and testing
conditions
Music
included
Behavior
(test scores)
•
Identical conditions
to control extraneous
variables
Independent variable
(Cause)
Dependent variable
(Effect)
Study and testing
conditions
No
music
Behavior
(test scores)
Is there a difference?
Figure 1.6
Elements of a simple psychological experiment to assess the
effects on test scores of music during study.
•
Table 1.5 Basic Ethical Guidelines
for Psychological Researchers
Do no harm.
Accurately describe risks to potential
participants.
Ensure that participation is voluntary.
Minimize any discomfort to participants.
Maintain confidentiality.
Do not unnecessarily invade privacy.
Use deception only when absolutely
necessary.
Remove any misconceptions caused by
deception (debrief ).
Provide results and interpretations to
participants.
Treat participants with dignity and respect.
amount of light, and so forth — must also be prevented from
affecting the outcome of an experiment. But how? Usually this is
done by making all conditions (except the independent variable)
exactly alike for both groups. When all conditions are the same
for both groups — except the presence or absence of music — then
any difference in the amount learned must be caused by the music
( Figure 1.6). (Psychology experiments sometimes raise ethical questions. See “That’s Interesting, but Is It Ethical” for more
information.)
•
Cause and Effect
Now let’s summarize. In an experiment, two or more groups of
subjects are treated differently with respect to the independent
variable. In all other ways they are treated the same. That is, extraneous variables are equated for all groups. The effect of the independent variable (or variables) on some behavior (the dependent
variable) is then measured. In a carefully controlled experiment,
the independent variable is the only possible cause for any effect
noted in the dependent variable. This allows clear cause-andeffect connections to be identified ( Figure 1.7).
•
Evaluating Results
group; tails, it’s the control group. This would result in few average differences in the number of people in each group who are
women or men, geniuses or dunces, hungry, hungover, tall, music
lovers, or whatever.
Other extraneous, or outside, variables — such as the amount
of study time, the temperature in the room, the time of day, the
How can we tell if the independent variable really made a difference? This problem is handled statistically. Reports in psychology
journals almost always include the statement, “Results were statistically significant.” What this means is that the obtained results
would occur very rarely by chance alone. To be statistically significant, a difference must be large enough so that it would occur by
Introduction to Psychology and Research Methods
Dependent Variable
A B C
A B C
35
nothing. Later, she assesses how much each participant learned.
Does this experiment seem valid? Actually, it is seriously flawed
for several reasons.
Research Participant Bias
Experimental Group
Control Group
Extraneous Variables
Independent Variable
1.7 Experimental control is achieved by balancing extraneous vari•ablesFigure
for the experimental group and the control group. For example, the average
age (A), education (B), and intelligence (C) of group members could be made the
same for both groups. Then we could apply the independent variable to the experimental group. If their behavior (the dependent variable) changes (in comparison
with the control group), the change must be caused by the independent variable.
chance in less than 5 experiments out of 100. (See the Statistics
Appendix for more information.) Of course, findings also become
more convincing when they can be replicated (repeated) by other
researchers.
Meta-Analysis
As you might guess, numerous studies are done on important topics in psychology. Although each study adds to our understanding,
the results of various studies don’t always agree. Let’s say we are
interested in whether males or females tend to be greater risk takers. A computer search would reveal that more than 100 studies
have investigated various types of risk-taking (for example, smoking, fast driving, or unprotected sex).
Is there a way to combine the results of the studies? Yes, a statistical technique called meta-analysis can be used to combine the
results of many studies as if they were all part of one big study
(Rosenthal & DiMatteo, 2001). In other words, a meta-analysis is
a study of the results of other studies. In recent years, meta-analysis
has been used to summarize and synthesize mountains of psychological research. This allows us to see the big picture and draw
conclusions that might be missed in a single, small-scale study. Oh,
and about that risk-taking question: A meta-analysis showed that
males do tend to take more risks than females (Byrnes, Miller, &
Schafer, 1999). (The most frequent last words uttered by deceased
young males is rumored to be, “Hey, watch this!”)
Double Blind — On Placebos
and Self-Fulfilling Prophecies
Gateway Question: What is a double-blind experiment?
Suppose a researcher hypothesizes that the drug amphetamine (a
stimulant) improves learning. She explains her hypothesis to her
participants and gives experimental group participants an amphetamine pill before they begin studying. Control group members get
Why? The experimental group took the drug and the control group
didn’t. Differences in the amount they learned must have been caused
by the drug, right? No, because the drug wasn’t the only difference
between the groups. For a start, because of what they were told,
participants in the experimental group likely expected to learn
more. Any observed differences between groups then may reflect
differences in expectation, not the actual effect of the drug. In a
well-designed experiment, you must be careful about what you
tell participants. Small bits of information might create research
participant bias, or changes in participants’ behavior caused by
the influence of their expectations.
Notice also that experimental group participants swallowed
a pill, and control participants did not. This is another form of
research participant bias. It could be that those who swallowed a
pill unconsciously expected to do better. After all, pills are medicine, aren’t they? This alone might have created a placebo effect
(changes in behavior caused by belief that one has taken a drug).
Suppose the researcher had not given the experimental group an
amphetamine pill and instead had given them a placebo (plahSEE-bo) or fake drug. Inactive substances such as sugar pills and
saline (saltwater) injections are commonly used as placebos. If a
placebo has any effect, it must be based on suggestion, rather than
chemistry (Thompson, 2005).
Placebo effects can be quite powerful. For instance, a saline
injection is 70 percent as effective as morphine in reducing pain.
That’s why doctors sometimes prescribe placebos — especially for
complaints that seem to have no physical basis. Placebos have been
shown to affect pain, anxiety, depression, alertness, tension, sexual
arousal, cravings for alcohol, and many other processes (Wampold
et al., 2005).
How could an inert substance have any effect? Placebos alter our
expectations, both conscious and unconscious, about our own
emotional and physical reactions. Because we associate taking
medicine with feeling better, we expect placebos to make us feel
better, too (Stewart-Williams, 2004). After a person takes a pla-
Statistical significance Experimental results that would rarely occur by
chance alone.
Meta-analysis A statistical technique for combining the results of many
studies on the same subject.
Research participant bias Changes in the behavior of research
participants caused by the unintended influence of their own
expectations.
Placebo effect Changes in behavior due to participant’s expectations
that a drug (or other treatment) will have some effect.
Placebo An inactive substance given in the place of a drug in
psychological research or by physicians who wish to treat a complaint
by suggestion.
CHAPTER 1
Royalty-Free/Corbis
36
The placebo effect is a major factor in medical treatments. Would you also expect
the placebo effect to occur in psychotherapy? (It does, which complicates studies
on the effectiveness of new psychotherapies.)
cebo, there is a reduction in brain activity linked with pain, so the
effect is not imaginary (Wager et al., 2004).
Controlling Research Participant Bias
How can you avoid research participant bias? To control for research
participant bias, we could use a single-blind experiment. In this
case, participants do not know if they are in the experimental or
the control group or if they are receiving a real drug or a placebo.
All participants are given the same instructions and everyone
gets a pill or injection. People in the experimental group get a
real drug, and those in the control group get a placebo. Because
participants are blind as to the hypothesis under investigation and
whether they received the drug, their expectations (conscious and
unconscious) are the same. Any difference in their behavior must
be caused by the drug. However, even this arrangement is not
enough, because researchers themselves sometimes affect experiments by influencing participants. Let’s see how this occurs.
Although the teachers were not conscious of any bias, apparently they subtly communicated their expectations to students.
Most likely, they did this through tone of voice, body language,
and by giving encouragement or criticism. Their “hints,” in turn,
created a self-fulfilling prophecy that affected the students. A selffulfilling prophecy is a prediction that prompts people to act
in ways that make the prediction come true. For instance, many
teachers underestimate the abilities of ethnic minority children,
which hurts the students’ chances for success (Weinstein, Gregory,
& Strambler, 2004). In short, people sometimes become what we
prophesy for them. It is wise to remember that others tend to live up
or down to our expectations for them ( Jussim & Harber, 2005).
The Double-Blind Experiment
Because of research participant bias and researcher bias, it is
common to keep both participants and researchers “blind.” In a
double-blind experiment neither subjects nor researchers know
who is in the experimental group or the control group, including
who received a drug and who took a placebo. Typically, someone
else conducts the experiment, including preparing the pills or
injections so that actual researchers don’t know until after testing who got what. This not only controls for research participant
bias, it also keeps researchers from unconsciously influencing
participants.
Double-blind testing has shown that about 50 percent of the
effectiveness of antidepressant drugs, such as the “wonder drug”
Prozac, is due to the placebo effect (Kirsch & Sapirstein, 1998).
Much of the popularity of herbal health remedies is also based on
the placebo effect (Seidman, 2001).
bridges
For more information about how psychologists study
placebos, see Chapter 13, page 449.
Researcher Bias
How could a researcher influence subjects?As we saw earlier, when
the experimenter explained her hypothesis to the participants, she
likely biased the results of the study. But even if a researcher uses
a single-blind procedure to avoid deliberately biasing participants,
researcher bias (changes in behavior caused by the unintended
influence of a researcher) remains a problem. In essence, experimenters run the risk of finding what they expect to find. This
occurs because humans are very sensitive to hints about what is
expected of them (Rosenthal, 1994).
Researcher bias even applies outside the laboratory. Psychologist Robert Rosenthal (1973) reports an example of how expectations influence people: At the U.S. Air Force Academy Preparatory
School, 100 airmen were randomly assigned to five different math
classes. Their teachers did not know about this random placement.
Instead, each teacher was told that his or her students had unusually high or low ability. Students in the classes labeled “high ability”
improved much more in math scores than those in “low-ability”
classes. Yet initially all the classes had students of equal ability.
KNOWL E DG E B U I L DE R
The Psychology Experiment
RECITE
1. To understand cause and effect, a simple psychological experiment is
based on creating two groups: the ______________________________
group and the _____________________________ group.
2. There are three types of variables to consider in an experiment:
______________________ variables (which are manipulated by the
experimenter), _____________________ variables (which measure
the outcome of the experiment), and _________________________
variables (factors to be excluded in a particular experiment).
3. A researcher performs an experiment to learn if room temperature
affects the amount of aggression displayed by college students
under crowded conditions in a simulated prison environment. In this
experiment, the independent variable is which of the following?
a. room temperature
b. the amount of aggression
c. crowding
d. the simulated prison environment
Continued
Introduction to Psychology and Research Methods
4. A procedure used to control both research participant bias and
researcher bias in drug experiments is the
a. correlation method
b. extraneous prophecy
c. double-blind technique
d. random assignment of subjects
REFLECT
Critical Thinking
5. There is a loophole in the statement, “I’ve been taking vitamin C tablets, and I haven’t had a cold all year. Vitamin C is great!” What is the
loophole?
6. People who believe strongly in astrology have personality characteristics that actually match, to a degree, those predicted by their
astrological signs. Can you explain why this occurs?
Relate
In a sense, we all conduct little experiments to detect cause-andeffect connections. If you are interested in cooking, for example, you
might try adding a particular spice to a meal on one occasion but not
another. The question then becomes, “Does the use of the spice (the
independent variable) affect the appeal of the meal (the dependent
variable)?” By comparing a spiced meal (the control group) with an
unspiced meal (the experimental group) you could find out if that
spice is worth using. Can you think of at least one informal experiment
you’ve run in the last month? What were the variables? What was the
outcome?
37
Naturalistic Observation
Psychologists sometimes actively observe behavior in a natural setting (the typical environment in which a person or animal lives).
For example, in 1960 Jane Goodall observed a chimpanzee use a
grass stem as a tool to remove termites from a termite mound (Van
Lawick-Goodall, 1971). Notice that naturalistic observation only
provides descriptions of behavior. In order to explain observations
we may need information from other research methods. Just the
same, Goodall’s discovery showed that humans are not the only
tool-making animals (Nakamichi, 2004).
Chimpanzees in zoos use objects as tools. Doesn’t that demonstrate
the same thing? Not necessarily. Naturalistic observation allows
us to study behavior that hasn’t been tampered with or altered by
outside influences. Only by observing chimps in their natural environment can we tell if they use tools without human interference.
Limitations
Doesn’t the presence of human observers affect the animals’ behavior?
Yes. The observer effect is a major problem. The observer effect
refers to changes in a subject’s behavior caused by an awareness
of being observed. Naturalists must be very careful to keep their
distance and avoid “making friends” with the animals they are
watching. Likewise, if you are interested in why automobile drivers
have traffic accidents, you can’t simply get in people’s cars and start
taking notes. As a stranger, your presence would probably change
the driver’s behaviors. When possible, the observer effect can be
minimized by concealing the observer.
Another solution is to use hidden recorders. One naturalistic
study of traffic accidents was done with video cameras installed in
Answers: 1. experimental, control 2. independent, dependent, extraneous 3. a 4. c 5. The statement implies that vitamin C prevents colds.
However, not getting a cold could just be a coincidence. A controlled
experiment with a group given vitamin C and a control group not taking
vitamin C would be needed to learn if vitamin C actually has any effect
on susceptibility to colds. 6. Belief in astrology can create a selffulfilling prophecy in which people alter their behaviors and selfconcepts to match their astrological signs (van Rooij, 1994).
Single-blind experiment An arrangement in which participants
remain unaware of whether they are in the experimental group or the
control group.
Nonexperimental Research
Methods — Different Strokes
Gateway Question: What nonexperimental research methods do
psychologists use?
Determining cause-and-effect relationships between variables lies
at the heart of explaining not just what we do, but why we do
it. For this reason, psychologists place a special emphasis on
controlled experimentation (experimental method). However,
because it is not always possible to conduct experiments, psychologists gather evidence and test hypotheses in many others ways
( Jackson, 2008). They observe behavior as it unfolds in natural
settings (naturalistic observation); they make measurements to
discover relationships between events (correlational method);
they study psychological problems and therapies in clinical settings (clinical method); and they use questionnaires to poll large
groups of people (survey method). Let’s see how each of these is
used to advance psychological knowledge.
Researcher bias Changes in subjects’ behavior caused by the
unintended influence of a researcher’s actions.
Self-fulfilling prophecy A prediction that prompts people to act in
ways that make the prediction come true.
Double-blind experiment An arrangement in which both participants
and experimenters are unaware of whether participants are in the
experimental group or the control group, including who might have
been administered a drug or a placebo.
Experimental method Investigating causes of behavior through
controlled experimentation.
Naturalistic observation Observing behavior as it unfolds in natural
settings.
Correlational method Making measurements to discover relationships
between events.
Clinical method Studying psychological problems and therapies in
clinical settings.
Survey method Using questionnaires and surveys to poll large groups
of people.
Observer effect Changes in a person’s behavior brought about by an
awareness of being observed.
38
CHAPTER 1
100 cars (Dingus et al., 2006). It turns out that most accidents are
caused by failing to look at the traffic in front of the car (eyes forward!). Hidden stationary video cameras have also provided valuable observations of many animal species. As recording devices
have become miniaturized, it has even become possible to attach
“critter cams” directly to many species, allowing observations to
be in a wide range of natural environments ( Figure 1.8). For
example, zoologist Christian Rutz and his colleagues outfitted shy
New Caledonian crows with “crow cams” to better understand
their use of tools to forage for food (Rutz et al., 2007). Apparently
humans and other primates are not the only tool-using species.
Observer bias is a related problem in which observers see what
they expect to see or record only selected details ( Jackson, 2008).
For instance, teachers in one classic study were told to watch
normal elementary school children who had been labeled (for the
study) as “learning disabled,” “mentally retarded,” “emotionally
disturbed,” or “normal.” Sadly, teachers gave the children very different ratings, depending on the labels used (Foster & Ysseldyke,
1976). In some situations, observer bias can have serious consequences (Spano, 2005). For example, a police officer expecting
criminal behavior might shoot a person who is reaching for his
wallet because he appears to be reaching for a gun.
A special mistake to avoid while observing animals is the anthropomorphic (AN-thro-po-MORE-fik) error. This is the error of
attributing human thoughts, feelings, or motives to animals—
especially as a way of explaining their behavior (Wynne, 2004). The
temptation to assume that an animal is “angry,” “jealous,” “bored,”
•
or “guilty” can be strong. If you have pets at home, you probably
already know how difficult it is to avoid anthropomorphizing. But it
can lead to false conclusions. For example, if your dog growls at your
girlfriend every time she visits, you might assume the dog doesn’t like
her. But maybe she wears a perfume that irritates the dog’s nose.
Psychologists doing naturalistic studies make a special effort
to minimize bias by keeping an observational record, or detailed
summary of data and observations. As suggested by the study of
traffic accidents and the use of “critter cams,” video recording
often provides the most objective record of all. Despite its problems, naturalistic observation can supply a wealth of information
and raise many interesting questions. In most scientific research it
is an excellent starting point.
Correlational Studies
Let’s say a psychologist notes an association between the IQs of
parents and their children, or between beauty and social popularity, or between anxiety and test performance, or even between
crime and the weather. In each case, two observations or events are
correlated (linked together in an orderly way). The Los Angeles
study of crime and temperature mentioned earlier in this chapter
is an example of a correlational study. Such studies evaluate
the degree of relationship, or correlation, between two existing
traits, behaviors, or events. First, two factors are measured. Then
a statistical technique is used to find their degree of correlation.
For example, we could find the correlation between the number
of hours spent practicing and sports performance during competitions. If the correlation is large, knowing how much a person
practices would allow us to predict his or her success in competition. Likewise, success in competition could be used to predict the
amount of practice.
Psychologists seek to identify relationships concerning memory, perception, stress, aging, therapy, and a host of similar topics.
Much of this book is a summary of such relationships.
Correlation Coefficients
How is the degree of correlation expressed? The strength and direction
of a relationship can be expressed as a coefficient of correlation.
This can be calculated as a number falling somewhere between
1.00 and 1.00. Drawing graphs of relationships can also help
clarify their nature ( Figure 1.9). If the number is zero or close to
zero, the association between two measures is weak or nonexistent
( see Figure 1.9c). For example, the correlation between shoe size
and intelligence is zero. (Sorry, size 12 readers.) If the correlation is
1.00, a perfect positive relationship exists ( see Figure 1.9e); if it
is –1.00, a perfect negative relationship has been discovered ( see
Figure 1.9a).
•
•
© Jolyon Troscianko 2006
•
Figure 1.8 New Caledonian crows wearing tiny “crow cams” barely half the
•weight
of a silver dollar have been recorded using twigs to forage for food
(Rutz et
al., 2007).
bridges
For more details about calculating and graphing
correlations, see the Statistics Appendix.
•
39
Introduction to Psychology and Research Methods
Correlations in psychology are
rarely perfect. But the closer the coefficient is to 1.00 or –1.00, the stronger
the relationship. For example, identical
twins tend to have almost identical IQs.
In contrast, the IQs of parents and their
children are only generally similar. The
correlation between the IQs of parents
and children is .35; between identical
twins it’s .86.
Correlation
Strength of relationship
Negative
Perfect
–1.00
Medium Small
–.30
–.10
Small Medium Large Very large
+.10 +.30
+.50 +.75
Perfect
+1.00
Y
Perfect
negative
relationship
X
(a)
Moderate
negative
relationship
No relationship
Moderate
positive
relationship
Perfect
positive
relationship
(b)
(c)
(d)
(e)
X
Figure 1.9 The correlation coefficient tells how strongly two measures are related. These graphs show a range of rela•tionships
between two measures, X and Y. If a correlation is negative, increases in one measure are associated with decreases
in the other. (As Y gets larger, X gets smaller.) In a positive correlation, increases in one measure are associated with increases
in the other. (As Y gets larger, X gets larger.) Graph b (“moderate negative relationship”) might result from comparing grades
in college (Y) with hours spent playing computer games (X): Higher anxiety is associated with lower scores. Graph c (“no relationship”) would result from plotting a person’s shoe size (Y) and his or her IQ (X). Graph d (“moderate positive relationship”)
could be a plot of grades in high school (Y) and grades in college (X) for a group of students: Higher grades in high school are
associated with higher grades in college.
What do the terms “positive” and
“negative” correlation mean? A positive
correlation shows that higher scores in one measure are matched by
higher scores in the other. For example, there is a moderate positive
correlation between high school grades and college grades; students
who do well in high school tend to do well in college (and the
reverse) (see Figure 1.9d). In a negative correlation, higher scores
in the first measure are associated with lower scores in the second. We
might observe, for instance, a moderate negative correlation between
the number of hours that students play computer games and grades.
That is, more play is associated with lower grades. (This is the wellknown computer-game-zombie effect; see Figure 1.9b).
Wouldn’t that show that playing computer games too much causes
lower grades?It might seem so, but as we saw previously, the best
way to be confident that a cause-and-effect relationship exists is to
perform a controlled experiment.
Z
Typical diet in
mental hospitals
•
•
Correlation and Causation
Correlational studies help us discover relationships and make predictions. However, correlation does not demonstrate causation (a
cause-effect relationship) (Elder, 2006). It could be, for instance,
that students who aren’t interested in their classes have more
time for computer games. If so, then their lack of study and lower
grades would both result from disinterest, not from excess game
playing. Just because one thing appears to be related to another
does not mean that a cause-and-effect connection exists.
Here is another example of mistaking correlation for causation:
What if a psychologist discovers that the blood of patients with
schizophrenia contains a certain chemical not found in the general
population? Does this show that the chemical causes schizophrenia? It may seem so, but schizophrenia could cause the chemical to
form. Or both schizophrenia and the chemical might be caused by
some unknown third factor, such as the typical diet in mental hospitals ( Figure 1.10). To reiterate, just because one thing appears
•
Zero
0.0
Y
bridges
Correlations between the IQs
of family members are used to
estimate the degree to which
intelligence is affected by
heredity and environment. See
Chapter 9, pages 312–313.
Positive
Very large Large
–.75
–.50
Figure 1.10 A correlation
•between
two variables might mean that
X causes Y, that Y causes X, or that a third
variable, Z, causes both X and Y.
Schizophrenia
Chemical
in blood
X
Y
Observer bias The tendency of an observer to distort observations or
perceptions to match his or her expectations.
Anthropomorphic error The error of attributing human thoughts,
feelings, or motives to animals, especially as a way of explaining their
behavior.
Observational record A detailed summary of observed events or a
videotape of observed behavior.
Correlation The existence of a consistent, systematic relationship
between two events, measures, or variables.
Correlational study A nonexperimental study designed to measure
the degree of relationship (if any) between two or more events,
measures, or variables.
Coefficient of correlation A statistical index ranging from 1.00 to
1.00 that indicates the direction and degree of correlation.
Positive correlation A statistical relationship in which increases in
one measure are matched by increases in the other (or decreases
correspond with decreases).
Negative correlation A statistical relationship in which increases in
one measure are matched by decreases in the other.
Causation The act of causing some effect.
40
CHAPTER 1
to cause another does not confirm that it does. The best way to be
confident that a cause-and-effect relationship exists is to perform
a controlled experiment.
The Clinical Method — One Case at a Time
It may be impractical, unethical, or impossible to use the experimental method to study rare events, such as unusual mental
disorders, childhood “geniuses,” or “rampage” school shootings
(Harding, Fox, & Mehta, 2002). In such instances, a case study
(an in-depth focus on a single subject) may be the best source of
information. Clinical psychologists rely heavily on case studies,
especially as a way to investigate mental disorders, such as depression or psychosis. Also, case studies of psychotherapy have provided many useful ideas about how to treat emotional problems
(Wedding & Corsini, 2005).
Case studies may sometimes be thought of as natural clinical
tests (accidents or other natural events that provide psychological data). Gunshot wounds, brain tumors, accidental poisonings,
and similar disasters have provided much information about the
human brain. One remarkable case from the history of psychology
is reported by Dr. J. M. Harlow (1868). Phineas Gage, a young
foreman on a work crew, had a 13-pound steel rod blown through
the front of his brain by a dynamite explosion ( Figure 1.11).
Amazingly, he survived the accident. Within 2 months Gage could
walk, talk, and move normally, but the injury forever changed his
personality. Instead of the honest and dependable worker he had
been before, Gage became a surly, foul-mouthed liar. Dr. Harlow
carefully recorded all details of what was perhaps the first in-depth
case study of an accidental frontal lobotomy (the destruction of
front brain matter).
•
•
Figure 1.11 Some of the earliest
information on the effects of damage to frontal areas of the brain came from a case study
of the accidental injury of Phineas Gage.
When a Los Angeles carpenter named Michael Melnick suffered a similar injury, he recovered completely, with no lasting ill
effects. Melnick’s very different reaction to a similar injury shows
why psychologists prefer controlled experiments and often use lab
animals for studies of the brain. Case studies lack formal control
groups. This, of course, limits the conclusions that can be drawn
from clinical observations.
Nevertheless, case studies can provide special opportunities to
answer interesting questions. For instance, a classic case study in
psychology concerns identical quadruplets, known as the Genain
sisters. In addition to having identical genes, all four women
became schizophrenic before age 25 (Rosenthal & Quinn, 1977).
The chances of identical quadruplets all becoming schizophrenic
are about 1 in 1.5 billion.
The Genains, who have been studied for more than 40 years,
were in and out of mental hospitals most of their lives. The fact
that they share identical genes suggests that mental disorders are
influenced by heredity. The fact that some of the sisters are more
disturbed than others suggests that environmental conditions also
affect mental illness. Indeed, Myra, the least ill of the four, was the
only sister who was able to avoid her father, an alcoholic who terrorized, spied on, and sexually molested the girls. Thus, cases like
theirs provide insights that can’t be obtained by any other means
(Mirsky et al., 2000).
bridges
See Chapter 14, pages 472–476, for more information about
the causes of schizophrenia.
Survey Method — Here, Have a Sample
Sometimes psychologists would like to ask everyone in the world a
few well-chosen questions: “Do you drink coffee? How often per
week?” “What form of discipline did your parents use when you
were a child?” “What is the most dishonest thing you’ve done?”
Honest answers to such questions can reveal much about people’s
behavior. But, because it is impossible to question everyone, doing
a survey is often more practical.
In the survey method, public polling techniques are used to
answer psychological questions (Tourangeau, 2004). Typically,
people in a representative sample are asked a series of carefully
worded questions. A representative sample is a small group
that accurately reflects a larger population. A good sample must
include the same proportion of men, women, young, old, professionals, blue-collar workers, Republicans, Democrats, whites,
African Americans, Native Americans, Latinos, Asians, and so on
as found in the population as a whole.
A population is an entire group of animals or people belonging to a particular category (for example, all college students or
all single women). Ultimately, we are interested in entire populations. But by selecting a smaller sample we can draw conclusions
about the larger group without polling each and every person.
Introduction to Psychology and Research Methods
41
Representative samples are often obtained
by randomly selecting who will be included
( Figure 1.12). (Notice that this is similar
to randomly assigning participants to groups
in an experiment.)
How accurate is the survey method? Modern
surveys such as the Gallup and Harris polls are
quite accurate. The Gallup poll has erred in its
election predictions by only 1.5 percent since
1954. However, if a survey is based on a biased
sample, it may paint a false picture. A biased
sample does not accurately reflect the population from which it was drawn. Surveys done by
magazines, websites, and online information
services can be quite biased. Surveys on the
Figure 1.12 If you were conducting a survey in which a person’s height might be an important variable,
use of guns done by O: The Oprah Magazine the upper, nonrandom sample would be very unrepresentative. The lower sample, selected using a table of ranand Guns and Ammo magazine would prob- dom numbers, better represents the group as a whole.
ably produce very different results — neither of
rassed? Replies to survey questions are not always accurate or
which would represent the general population. That’s why psycholtruthful. Many people show a distinct courtesy bias (a tendency to
ogists using the survey method go to great lengths to ensure that
give “polite” or socially desirable answers). For example, answers
their samples are representative. Fortunately, people can often be
to questions concerning sex, drinking or drug use, income, and
polled by telephone, which makes it easier to obtain large samples.
church attendance tend to be less than truthful. Likewise, the
Even if one person out of three refuses to answer survey questions,
week after an election, more people will say they voted than actuthe results are still likely to be valid (Hutchinson, 2004).
ally did (Hutchinson, 2004).
In recent years, 93 percent of human subjects in psychology
experiments have been recruited from introductory psychology
Summary
courses (Sieber & Saks, 1989). The majority of these subjects
have been white members of the middle class, and most of the
Despite their limitations, surveys frequently produce valuable
researchers themselves have been white males (Guthrie, 2004).
information. For instance, the survey method has been used to
None of this automatically invalidates the results of psycholfind out about the attitudes of Muslims in the Middle East toward
ogy experiments. However, it may place some limitations on
U.S. policies in the region and to clarify the debate about Islam
their meanings. (See “Is There a Gender Bias in Psychologiand violence that has arisen since the terrorist attacks of 9/11
cal Research?”) The distinguished psychologist Edward Tolman
(Haddad, 2003). To sum up, the survey method can be a powerful
once noted that much of psychology is based on two sets of
research tool. Like other methods, it has limitations, but new techsubjects: rats and college sophomores. Tolman urged scientists
niques and strategies are providing valuable information about our
to remember that rats are certainly not people and that college
behavior (Kahneman et al., 2004).
sophomores may not be!
Is so much emphasis on science really necessary in psychology? In a
word, yes. As we have seen, science is a powerful way of asking quesInternet Surveys
tions about the world and getting trustworthy answers. ( Table 1.6
Recently, psychologists have started doing surveys and experisummarizes many of the important ideas we have covered.)
ments on the Internet. Web-based research can be a cost-effective
way to reach very large groups of people. Internet studies have provided interesting information about topics such as anger, decision
making, racial prejudice, what disgusts people, religion, sexual
Case study An in-depth focus on all aspects of a single person.
attitudes, and much more. Biased samples can limit web-based
Survey method The use of public polling techniques to answer
research (because it isn’t easy to control who actually answers your
psychological questions.
online questionnaire), but psychologists are finding ways to gather
Representative sample A small, randomly selected part of a larger
valid information with it (Birnbaum, 2004; Whitaker, 2007).
population that accurately reflects characteristics of the whole
•
•
•
Social Desirability
Even well-designed surveys may be limited by another problem.
If a psychologist were to ask you detailed questions about your
sexual history and current sexual behavior, how accurate would
your replies be? Would you exaggerate? Would you be embar-
population.
Population An entire group of animals or people belonging to a
particular category (for example, all college students or all married
women).
Biased sample A subpart of a larger population that does not
accurately reflect characteristics of the whole population.
42
CHAPTER 1
HUM AN D IVERS I T Y
Is There a Gender Bias in Psychological Research?
As you read through this book you may find
yourself wondering whether or not a particular concept, theory, or research finding
applies equally well to women and men, to
members of various races or ethnic groups,
or to people of different ages or sexual orientations. Human Diversity boxes like this one
will help you be more reflective about our
multicultural, multifaceted society. Here, let’s
begin with a basic question: Is there is a gender bias in the research process itself?
Many doctors continue to recommend
that adults take an aspirin a day to help prevent a heart attack. Both men and women are
given this advice. The problem? Not a single
woman was included in the original sample
on which the advice is based. Although
females make up more than half the population, they continue to be neglected in
psychological and medical research (Hyde,
2004).
This oversight is just one form of gender bias in research. This term refers to
the tendency for females to be underrepresented as research subjects and female
Table 1.6
topics to be ignored by many investigators.
Consequently, the investigators assumed
that conclusions based on men also apply
to women. But without directly studying
women it is impossible to know how often
this assumption is wrong. A related problem
occurs when researchers combine results
from men and women. Doing so can hide
important male–female differences. An additional problem is that unequal numbers of
men and women may volunteer for some
kinds of research. For example, in studies of
sexuality, more male college students volunteer to participate than females (Wiederman,
1999). What a surprise!
Another form of gender bias in research
occurs when women are underrepresented
among the researchers themselves. In one
example, Laurence Kohlberg (1969) proposed a theory about how we develop moral
values. His studies suggested that women
were morally “immature” because they were
not as concerned with justice as men were.
However, few women were involved in doing
the studies and Kohlberg merely assumed
that theories based on men also apply to
women. In response, Carol Gilligan (1982)
provided evidence that women were more
likely to make moral choices based on caring,
rather than justice. From this point of view,
it was men who were morally immature.
Today, we recognize that both justice and
caring perspectives may be essential to adult
wisdom. (See Chapter 3, pages 104–106, for
more details.)
Similar biases exist concerning the race,
ethnicity, age, and sexual orientation of
researchers and participants in psychological
research (Denmark, Rabinowitz, & Sechzer,
2005; Guthrie, 2004). Far too many conclusions are created by and/or based on small
groups of people who do not represent the
rich tapestry of humanity. However, the solution to such problems is straightforward: We
need to encourage a wider array of people
to become researchers and, when possible,
researchers need to include a wider array
of people in their studies. In recognition of
human diversity, many researchers are doing
just that (Reid, 2002).
• Comparison of Psychological Research Methods
Method
Advantages
Disadvantages
Experimental
Method
Clear cause-and-effect relationships can be identified; powerful
controlled observations can be staged; no need to wait for
natural event
May be somewhat artificial; some natural behavior not easily
studied in laboratory (field experiments may avoid these
objections)
Naturalistic
Observation
Behavior is observed in a natural setting; much information
is obtained, and hypotheses and questions for additional
research are formed
Little or no control is possible; observed behavior may be altered
by the presence of the observer; observations may be biased;
causes cannot be conclusively identified
Correlational
Method
Demonstrates the existence of relationships; allows prediction;
can be used in lab, clinic, or natural setting
Little or no control is possible; relationships may be coincidental;
cause-and-effect relationships cannot be confirmed
Clinical Method
Takes advantage of “natural clinical trials” and allows investigation
of rare or unusual problems or events
Little or no control is possible; does not provide a control group
for comparison; subjective interpretation is often necessary; a
single case may be misleading or unrepresentative
Survey Method
Allows information about large numbers of people to be gathered; can address questions not answered by other approaches
Obtaining a representative sample is critical and can be difficult
to do; answers may be inaccurate; people may not do what
they say or say what they do
A Look Ahead
To help you get the most out of psychology, each chapter of this
text includes a Psychology in Action section like the one that follows. There you will find ideas you can actually use, now or in the
future. To complete the topics we have been discussing, let’s take
a critical look at information reported in the popular press. You
should find this an interesting way to conclude our opening tour
of psychology and its methods.
Introduction to Psychology and Research Methods
Nonexperimental Research Methods
RECITE
1. Two major problems in naturalistic observation are the effects of the
observer and observer bias. T or F?
2. The ____________________________ fallacy involves attributing
human feelings and motives to animals.
3. Correlation typically does not demonstrate causation. T or F?
4. Which correlation coefficient represents the strongest relationship?
a. 0.86
b. 0.66
c. 0.10
d. 0.09
5. Case studies can often be thought of as natural tests and are frequently used by clinical psychologists. T or F?
6. For the survey method to be valid, a representative sample of people
must be polled. T or F?
7. A problem with the survey method is that answers to questions may
not always be _______________________________ or
_______________________________.
REFLECT
Critical Thinking
8. A psychologist conducting a survey at a shopping mall (The Gallery
of Wretched Excess) flips a coin before stopping passersby. If the
coin shows heads, he interviews the person; if it shows tails, he skips
that person. Has the psychologist obtained a random sample?
9. Is attributing mischievous motives to a car that is not working properly a thinking error similar to anthropomorphizing?
Relate
Google “critter cam” and find one you can watch. What species are you
watching? What behaviors might you observe and record?
See if you can identify at least one positive relationship and one negative relationship that involves human behavior.
Have you ever known someone who suffered a brain injury or disease? How did his or her behavior change? Was the change clear-cut
enough to serve as a natural clinical test?
Have you ever been asked to complete a survey? Did you do it or did
you refuse? If you refused, do you think your refusal influenced the final
results of the survey? What would it say about accuracy if lots of people
refused to complete the survey? If you completed the survey, were you
honest about your answers? What would it say about accuracy if lots of
people refused to answer accurately?
Answers: 1. T 2. anthropomorphic 3. T 4. a 5. T 6. T 7. accurate, truthful
8. The psychologist’s coin flips might produce a reasonably good sample
of people at the mall. The real problem is that people who go to the mall
may be mostly from one part of town, from upper income groups, or
from some other nonrepresentative group. The psychologist’s sample is
likely to be seriously flawed. 9. Yes. It appears to be difficult for humans
to resist thinking of other species and even machines in human terms.
K N O WL E D GE B U I L D E R
43
P S YC H O L OGY IN A CT ION
Psychology in the Media — Separating Fact from Fiction
Gateway Question: How good is
psychological information found in the
popular media?
Psychology is a popular topic in contemporary
media. Unfortunately, much of what you will
encounter is based on entertainment value
rather than critical thinking or science. Here
are some suggestions for separating highquality information from misleading fiction:
Suggestion 1: Be skeptical. Have you ever
played the game called “telephone” or “pass it
down”? You know, one person whispers a sentence to someone else who, in turn, whispers
it on down the line. Usually, when the person
at the end of the line repeats the message it
has been humorously distorted. Similarly,
modern media, and especially the Internet,
function as a giant “echo chamber” awash
with rumors, hoaxes, half-truths, and urban
legends like the one about giant alligators living in New York sewers.
One of our all-time favorites was a story
about the health department in Oregon seeking a Klingon interpreter for mental health
patients who only speak in the fictional language used on the Star Trek TV series. This
tale started when a newspaper reported that
Klingon was on a list of languages that some
psychiatric patients claimed they could speak.
The article specifically noted that “in reality,
no patient has yet tried to communicate in
Klingon.” Nevertheless, as the story echoed
around the web, the idea that Oregon was
looking for someone fluent in Klingon had
become a “fact” (O’Neill, 2003).
Reports in the popular media tend to be
made uncritically and with a definite bias
toward reporting “astonishing” findings and
telling interesting stories. Remember, saying “That’s incredible” means “That’s not
believable” — which is often true.
Suggestion 2: Consider the source of information.
It should come as no surprise that information
used to sell a product often reflects a desire for
profit rather than the objective truth. Here is
a typical advertising claim: “Government tests
prove that no sleep medicine is stronger or
more effective than Coma.” A statement like
this usually means that there was no difference
between Coma and the other products tested.
No other sleep aid was stronger or more effective. But none was weaker either.
Keep the source in mind when reading
the claims of makers of home biofeedback
machines, sleep-learning devices, subliminal
CDs, and the like. Remember that psychological services may be merchandised as well. Be
wary of expensive courses that promise instant
mental health and happiness, increased efficiency, memory, extrasensory perception (ESP)
or psychic ability, control of the unconscious
mind, an end to smoking, and so on. Usually
they are promoted with a few testimonials and
many unsupported claims (Lilienfeld, 2005).
Psychic claims should be viewed with special caution. Stage mentalists make a living
by deceiving the public. Understandably, they
are highly interested in promoting belief in
their nonexistent powers. The same is true
of the so-called psychic advisers promoted in
TV commercials. These charlatans make use
of the Barnum effect (the tendency to consider personal descriptions accurate if they are
stated in general terms) to create an illusion
Gender bias (in research) A tendency
for females and female issues to be
underrepresented in research, psychological
or otherwise.
CHAPTER 1
that they know private information about the
people who call them (Nickell, 2001).
Google magician James Randi’s Million Dollar Challenge. Randi is offering
$1,000,000 to anyone demonstrating such
abilities under controlled conditions. Are you
surprised to learn that no one has even passed
the preliminary tests yet?
Suggestion 3: Beware of oversimplifications, especially those motivated by monetary gain. Courses
or programs that offer a “new personality in
three sessions,” “six steps to love and fulfillment
in marriage,” or some newly discovered “secret
for unlocking the powers of the mind and the
universe” should be immediately suspect.
An excellent example of oversimplification is provided by websites devoted to a
video that promises to reveal “the secret to
unlimited joy, health, money, relationships,
love, youth: everything you have ever wanted.”
According to these sites, all you need to do
is put your desires out to the universe and
the universe must respond by granting your
wishes. And all it will cost you is the price of
the video. (It’s no secret that the promoters
are the real winners in this game.)
Suggestion 4: Remember, “for example” is no proof.
After reading this chapter you should be sensitive to the danger of selecting single examples.
If you read, “Law student passes state bar exam
using sleep-learning device,” don’t rush out
to buy one. Systematic research showed long
ago that these devices are of little or no value
(Druckman & Bjork, 1994). A corollary to this
suggestion is to ask if the reported observations
are important or widely applicable.
Examples, anecdotes, single cases, and testimonials are all potentially deceptive. According to numerous testimonials, believers in the
power of the “secret” described earlier have
been showered with money, success, and happiness immediately after viewing the video.
Unfortunately, such individual cases (or even
several) tell nothing about what is true in
general (Stanovich, 2007). How many people
didn’t win the lottery after buying the video?
Similarly, studies of large groups of people
show that smoking increases the likelihood
of lung cancer. It doesn’t matter if you know a
lifelong heavy smoker who is 95 years old. The
general finding is the one to remember.
Suggestion 5: Ask yourself if there was a control
group. The key importance of a control group
in any experiment is frequently overlooked by
the unsophisticated — an error to which you
are no longer susceptible. The popular media
are full of reports of “experiments” performed
without control groups: “Talking to Plants
Speeds Growth”; “Special Diet Controls
Hyperactivity in Children”; “Graduates of
Firewalking Seminar Risk Their Soles.”
Consider the last example for a moment.
Expensive commercial courses have long been
promoted to teach people to walk barefoot
on hot coals. (Why anyone would want to
do this is itself an interesting question.) Firewalkers supposedly protect their feet with a
technique called “neurolinguistic programming.” Many people have paid good money
to learn the technique, and most do manage
a quick walk on the coals. But is the technique necessary? And is anything remarkable
happening? We need a comparison group.
Fortunately, physicist Bernard Leikind has
provided one. Leikind showed with volunteers that anyone (with reasonably callused
feet) can walk over a bed of coals without
being burned. The reason is that the coals,
which are light, fluffy carbon, transmit little
heat when touched. The principle involved is
similar to briefly putting your hand in a hot
oven. If you touch a pan, you will be burned
because metal transfers heat efficiently. But if
your hand stays in the heated air you’ll be fine
because air transmits little heat (Kida, 2006;
Mitchell, 1987). Mystery solved.
thing caused another just because they are
correlated. In spite of this, you will see many
claims based on questionable correlations.
Here’s an example of mistaking correlation
for causation: Jeanne Dixon, a well-known
astrologer, once answered a group of prominent scientists — who had declared that there
is no scientific foundation for astrology — by
saying, “They would do well to check the
records at their local police stations, where
they will learn that the rate of violent crime
rises and falls with lunar cycles.” Dixon, of
course, believes that the moon affects human
behavior.
If it is true that violent crime is more frequent at certain times of the month, doesn’t
that prove her point? Far from it. Increased
crime could be due to darker nights, the fact
that many people expect others to act crazier,
or any number of similar factors. Besides, direct
studies of the alleged “lunar effect” have shown
that it doesn’t occur (Dowling, 2005). Moonstruck criminals, influenced by “a bad moon
rising,” are a fiction (Iosif & Ballon, 2005).
Suggestion 7: Be sure to distinguish between
observation and inference. If you see a person
crying, is it correct to assume that she or he
is sad? Although it seems reasonable to make
this assumption, it is actually quite risky. We
can observe objectively that the person is crying, but to infer sadness may be in error. It
could be that the individual has just peeled
5 pounds of onions. Or maybe he or she just
won a million-dollar lottery or is trying contact lenses for the first time.
Psychologists, politicians, physicians, scientists, and other experts often go far beyond
the available facts in their claims. This does
not mean that their inferences, opinions, and
interpretations have no value; the opinion
of an expert on the causes of mental illness,
criminal behavior, learning problems, or
whatever can be revealing. But be careful to
distinguish between fact and opinion.
Suggestion 6: Look for errors in distinguishing
between correlation and causation. As you now
know, it is dangerous to presume that one
© John Nordell/The Image Works
44
Firewalking is based on simple physics, not on any form
of supernatural psychological control. The temperature
of the coals may be as high as 1,200º F. However, coals
are like the air in a hot oven: They are very inefficient at
transferring heat during brief contact.
Summary
We are all bombarded daily with such a
mass of new information that it is difficult
to absorb it. The available knowledge, even
in a limited area like psychology, biology,
medicine, or contemporary hip-hop music, is
so vast that no single person can completely
know and comprehend it. With this situation in mind, it becomes increasingly important that you become a critical, selective, and
informed consumer of information.
Introduction to Psychology and Research Methods
Psychology in the Media
RECITE
1. Popular media reports usually stress objective accuracy. T or F?
2. Stage mentalists and psychics often use deception in their “acts.” T or
F?
3. Blaming the lunar cycle for variations in the rate of violent crime is
an example of mistaking correlation for causation. T or F?
4. If a psychology student uses a sleep-learning device to pass a midterm exam, it proves that the device works. T or F?
REFLECT
Critical Thinking
5. Mystics have shown that fresh eggs can be balanced on their large
ends during the vernal equinox when the sun is directly over the
equator, day and night are equal in length, and the world is in perfect balance. What is wrong with their observation?
chapter in review
Psychology is the science of behavior and mental processes.
Psychologists gather scientific data in order to describe, understand,
predict, and control behavior.
6. Many parents believe that children become “hyperactive” when they
eat too much sugar, and some early studies seemed to confirm this
connection. However, we now know that eating sugar rarely has any
effect on children. Why do you think that sugar appears to cause
hyperactivity?
Relate
Do you tend to assume that a statement must be true if it is in print, on
television, or made by an authority? How actively do you evaluate and
question claims found in the media? Could you be a more critical consumer
of information? Should you be a more critical consumer of information?
Answers: 1. F 2. T 3. T 4. F 5. The mystics have neglected to ask if eggs
can be balanced at other times. They can be balanced any time you
like. The lack of a control group gives the illusion that something amazing is happening, but the equinox has nothing to do with egg balancing (Halpern, 2003). 6. This is another case of mistaking correlation
for causation. Children who are hyperactive may eat more sugar (and
other foods) to fuel their frenetic activity levels.
K N O WL E D GE B U I L D E R
45
Gateways to Psychology
publish results. Scientific debate and theories suggest new hypotheses, which lead to further research.
• Psychologists are professionals who create and apply psychological knowledge. Psychologists engage in critical thinking as
they systemically gather and analyze
• Psychology spans a wide variety of specialty areas of research.
• Some psychologists are directly interested in animal behavior.
Others study animals as models of human behavior.
• As a science, psychology’s goals are to describe, understand,
predict, and control behavior.
• Because the scientific method is a powerful way to observe the
natural world and draw valid conclusions, scientific research
provides the highest quality information about behavior.
• In the scientific method, systematic observation is used to test
hypotheses about behavior and mental events.
• Concepts must be defined operationally before they can be
studied empirically.
• The results of scientific studies are made public so that others
can evaluate them, learn from them, and use them to produce
further knowledge.
Critical thinking is the ability to reflect on, evaluate, compare, analyze,
critique, and synthesize information. Critical thinking is central to the
scientific method, to psychology, and to effective behavior in general.
The field of psychology emerged 130 years ago when researchers
began to directly study and observe psychological events.
• To judge the validity of a claim, it is important to gather evidence for and against the claim and to evaluate the quality of
the evidence.
Pseudopsychologies are unfounded systems that resemble psychology. Unlike psychology, pseudopsychologies change little over time
because followers seek evidence that appears to confirm their beliefs
and avoid evidence that contradicts their beliefs.
• Numerous pseudopsychologies are frequently confused with
valid psychology. Belief in pseudopsychologies is based in part
on uncritical acceptance, the fallacy of positive instances, and
the Barnum effect.
Psychological research begins by defining problems and proposing
hypotheses. Next, researchers gather evidence, test hypotheses, and
• The first psychological laboratory was established in Germany
by Wilhelm Wundt, who studied conscious experience.
• The first school of thought in psychology was structuralism, a
kind of “mental chemistry” based on introspection.
• Structuralism was followed by functionalism, behaviorism,
and Gestalt psychology.
• Psychodynamic approaches, such as Freud’s psychoanalytic
theory, emphasize the unconscious origins of behavior.
• Humanistic psychology accentuates subjective experience,
human potentials, and personal growth.
• Even though most of the early psychologists were men, women
have contributed to psychology from the beginning.
Three complementary streams of thought in modern psychology are
the biological perspective, including biopsychology and evolutionary
psychology; the psychological perspective, including behaviorism,
46
CHAPTER 1
cognitive psychology, the psychodynamic approach, and humanism;
and the sociocultural perspective.
• There is an eclectic blending of sviewpoints within psychology.
• Psychologists have recently begun to formally study positive
aspects of human behavior, or positive psychology.
• Most of what we think, feel, and do is influenced by the social
and cultural worlds in which we live.
There are dozens of specialties in psychology including clinical, counseling, industrial, educational, consumer, school, developmental,
engineering, medical, environmental, forensic, community, psychometric, and experimental psychology.
• Although psychologists, psychiatrists, psychoanalysts, and
counselors all work in the field of mental health, their training
and methods differ considerably.
• Psychological research may be basic or applied.
Experiments involve two or more groups of subjects that differ only
with regard to the independent variable. Effects on the dependent
variable are then measured. All other conditions (extraneous variables) are held constant.
• Since the independent variable is the only difference between
the experimental group and the control group, it is the only
possible cause of a change in the dependent variable.
• The design of experiments allows cause-and-effect connections
to be clearly identified.
• Psychological research must be done ethically, in order to protect the rights, dignity, and welfare of participants.
• To be taken seriously, the results of an experiment must be statistically significant (they would occur very rarely by chance alone).
In a double-blind experiment, neither the research participants nor
the researchers collecting data know who was in the experimental
group or the control group, allowing valid conclusions to be drawn.
• Research participant bias is a problem in some studies. The placebo
effect is also a factor, especially in experiments involving drugs.
• A related problem is researcher bias. Researcher expectations
can create a self-fulfilling prophecy, in which a participant
changes in the direction of the expectation.
Psychologists also rely on naturalistic observation, the correlational
method, case studies, and the survey method.
• Unlike controlled experiments, nonexperimental methods
usually cannot demonstrate cause-and-effect relationships.
• Naturalistic observation is a starting place in many investigations.
• Two problems with naturalistic observation are the effects of
the observer on the observed and observer bias.
• In the correlational method, relationships between two traits,
responses, or events are measured and a correlation coefficient
is computed to gauge the strength of the relationship.
• Correlations allow prediction but do not show cause and effect.
• Relationships in psychology may be positive or negative.
• Case studies provide insights into human behavior that can’t
be gained by other methods.
• In the survey method, people in a representative sample are
asked a series of carefully worded questions.
• Obtaining a representative sample of people is crucial when
the survey method is used to study large populations.
Information in the mass media varies greatly in quality and accuracy
and should be approached with skepticism and caution.
• It is essential to critically evaluate information from popular
sources (or from any source, for that matter) in order to separate facts from fallacies.
• Problems in media reports are often related to biased or unreliable sources of information, uncontrolled observation, misleading correlations, false inferences, oversimplification, use of
single examples, and unrepeatable results.
Web Resources
For an up-to-date list of direct links to interesting sites, including
those listed here, visit the student companion site for this book at
www.cengage.com/psychology/coon
What Is Psychology? Discusses psychology as a science, with links to
other articles about various branches of psychology.
Critical Thinking in Everyday Life: 9 Strategies Some useful critical
thinking strategies, along with many other articles on aspects of critical thinking.
Today in the History of Psychology Events in the history of psychology by the date, including podcasts.
Careers in Psychology Marky Lloyd’s Careers in Psychology Page.
The Experimental Method An introduction to experimental
research methods.
Psychological Research on the Net Find and complete a survey study.
That’s Infotainment! Article about sensationalism in the news media.
Interactive Learning
Introduction to Psychology: Gateways to Mind and Behavior Book
Companion Website
www.cengage.com/psychology/coon
Visit your book companion website, where you will find flash cards,
practice quizzes, web links, and more to help you study.
Just what you need to know NOW!
Spend time on what you need to master rather than on information you already have learned. Take a pre-test for this chapter, and
CengageNOW will generate a personalized study plan based on
your results. The study plan will identify the topics you need to
review and direct you to online resources to help you master those
topics. You can then take a post-test to help you determine the
concepts you have mastered and what you will need to work on.
Try it out! Go to www.cengage.com/login to sign in with an access
code or to purchase access to this product.
CHAPTER
2
Brain and Behavior
Gateway Theme
Brain activity is the source of human consciousness, intelligence, and behavior.
Hill Street Studios/Photolibrary
Gateway Questions
• How do nerve cells operate and communicate?
• What are the major parts of the nervous system?
• How is the brain studied?
• Why is the human cerebral cortex so important, and what
•
•
•
What are the major parts of the subcortex?
Does the glandular system affect behavior?
In what ways do right- and left-handed individuals
differ?
are its parts?
47
preview
Finding Music in Walnut Grapefruit Tofu
Your authors recently shared an evening together in Tucson,
Arizona, watching some fiery Spanish flamenco. We both had
brains on our minds. (Really!) The guitarist and dancer were
passionate and brilliant. If they had been athletes, you would
say they were “in the zone.” Of course, in everything from classical to jazz to hip-hop, musicians regularly make music that
no machine could duplicate. A virtual Bruce Springsteen? A
mechanical Beyoncé? We doubt it. That’s why music is such a
good example of the central role the brain plays in all that is
human.
Your 3-pound brain is wrinkled like a walnut, the size of a
grapefruit, and the texture of tofu. The next time you are in a
market that sells beef brains, stop and have a look. What you
will see is similar to your own brain, only smaller. How could
Neurons — Building a “Biocomputer”
Gateway Question: How do nerve cells operate and communicate?
While they may seem far removed from your daily life, 100 billion
tiny neurons (NOOR-ons: individual nerve cells) make up your
brain. Neurons carry information from the senses to the brain,
where they process it. They also activate muscles and glands. Yet, a
single neuron is not very smart — it would take many just to make
you blink. Millions of neurons must send messages at the same
time to produce even the most fleeting thought. When a musician
such as Eric Clapton plays a guitar riff, literally billions of neurons
may be involved (Kalat, 2007).
Your brainpower arises because individual neurons link to
one another in tight clumps and long “chains.” Each neuron
receives messages from many others and sends its own message on.
Everything you think, feel, or do can be traced back to electrical
impulses flashing through spidery networks of neurons. When
neurons form vast networks, they produce intelligence and consciousness. Let’s see how neurons operate and how the nervous
system is “wired.”
Like miniature cables, axons carry messages through the brain and
nervous system. Altogether, your brain contains about 3 million
miles of axons (Rosenzweig, Breedlove, & Watson, 2004).
Axons “branch out” into smaller fibers ending in bulb-shaped
axon terminals. By forming connections with the dendrites and
somas of other neurons, axon terminals allow information to pass
from neuron to neuron.
Now let’s summarize with a metaphor. Imagine that you are
standing in a long line of people who are holding hands. A person
on the far right end of the line wants to silently send a message to
the person on the left end. She does this by pressing the hand of
the person to her left, who presses the hand of the person to his
left, and so on. The message arrives at your right hand (your dendrites). You decide whether to pass it on. (You are the soma.) The
message goes out through your left arm (the axon). With your left
hand (the axon terminals), you squeeze the hand of the person to
your left, and the message moves on.
The Nerve Impulse
Electrically charged molecules called ions (EYE-ons) are found inside
each neuron ( Figure 2.2). Other ions lie outside the cell. Some ions
have a positive electrical charge, and some are negative. When a neuron is inactive, more of these “plus” charges exist outside the neuron
and more “minus” charges exist inside. As a result, the inside of each
neuron in your brain has an electrical charge of about minus 70 millivolts. (A millivolt is one thousandth of a volt.) This charge allows
each neuron in your brain to act like a tiny biological battery.
The electrical charge of an inactive neuron is called its resting
potential. But neurons seldom get much rest: Messages arriving
from other neurons raise and lower the resting potential. If the
electrical charge rises to about minus 50 millivolts, the neuron
•
Parts of a Neuron
What does a neuron look like? What are its main parts? No two neurons are exactly alike, but most have four basic parts ( Figure 2.1).
The dendrites (DEN-drytes), which look like tree roots, receive
messages from other neurons. The soma (SOH-mah: cell body)
does the same. In addition, the soma sends messages of its own
(nerve impulses) down a thin fiber called the axon (AK-sahn).
Some axons are only .1 millimeter long. (That’s about the width
of a pencil line.) Others stretch up to a meter through the nervous
system. (From the base of your spine to your big toe, for instance.)
•
48
such a squishy little blob of tissue allow us to make music of
exquisite beauty? To seek a cure for cancer? To fall in love? Or to
read a book like this one?
Each of the billions of nerve cells in your brain is linked to
thousands of others. The resulting network allows you to process immense amounts of information. In fact, there may be
more possible pathways between the neurons in your brain
than there are stars in the visible universe! Undeniably, the
human brain is the most amazing of all computers.
Scientists use the power of the brain to study the brain. Yet,
even now we must wonder if the brain will ever completely
understand itself. Nevertheless, answers to many age-old questions about the mind, consciousness, and knowledge lie buried
within the brain. Let’s visit this fascinating realm.
Brain and Behavior
49
2.1 A neuron, or nerve
•cell.Figure
In the right foreground you can
Synapse (see Figure 2.6
for an enlarged view)
Other neuron
Axon terminals
see a nerve cell fiber in cross section.
The upper left photo gives a more realistic picture of the shape of neurons.
Nerve impulses usually travel from the
dendrites and soma to the branching
ends of the axon. The nerve cell shown
here is a motor neuron. The axons of
motor neurons stretch from the brain
and spinal cord to muscles or glands of
the body.
Myelin
Nerve impulse
Neurilemma
Soma
(cell body)
Nerve impulse
Axon collateral
(branch)
Axon
Nerve cell fiber
Myelin sheath
Axon
Dendrites
•
will reach its threshold, or trigger point for firing. (See Figure
2.2.) It’s as if the neuron says, “Ah ha! It’s time to send a message to
my neighbors.” When a neuron reaches about 50 millivolts, an
action potential, or nerve impulse, sweeps down the axon at up to
200 miles per hour ( Figure 2.3). That may seem fast, but it still
takes at least a split second to react. That’s one reason why hitting a
95-mile-per-hour major league fastball is so difficult.
What happens during an action potential? The axon membrane
is pierced by tiny tunnels or “holes,” called ion channels. Normally, these tiny openings are blocked by molecules that act like
“gates” or “doors.” During an action potential, the gates pop open.
This allows sodium ions (Na) to rush into the axon (Carlson,
2007). The channels first open near the soma. Then gate after
gate opens down the length of the axon as the action potential zips
along ( Figure 2.4).
Each action potential is an all-or-nothing event (a nerve impulse
occurs completely or not at all). You might find it helpful to picture the axon as a row of dominoes set on end. Tipping over the
dominoes is an all-or-nothing act. Once the first domino drops,
a wave of falling blocks will zip rapidly to the end of the line.
Similarly, when a nerve impulse is triggered near the soma, a wave
of activity (the action potential) travels down the length of the
axon. This is what happens in long chains of neurons as a flamenco
dancer’s brain tells her feet what to do next, beat after beat.
•
•
After each nerve impulse, the cell briefly dips below its resting
level and it becomes less willing to fire. This negative after-potential occurs because potassium ions (K) flow out of the neuron
while the membrane gates are open. (See Figure 2.4.) After a
nerve impulse, ions flow both into and out of the axon, recharging
it for more action. In our model, it takes an instant for the row of
dominoes to be set up again. Soon, however, the axon is ready for
another wave of activity.
•
Neuron An individual nerve cell.
Dendrites Neuron fibers that receive incoming messages.
Soma The main body of a neuron or other cell.
Axon Fiber that carries information away from the cell body of a
neuron.
Axon terminals Bulb-shaped structures at the ends of axons that form
synapses with the dendrites and somas other neurons.
Resting potential The electrical charge of a neuron at rest.
Threshold The point at which a nerve impulse is triggered.
Action potential The nerve impulse.
Ion channels Tiny openings through the axon membrane.
Negative after-potential A drop in electrical charge below the resting
potential.
50
CHAPTER 2
Action
potential
Membrane potential
(in millivolts)
+30
•
0
Resting
potential
Negative
after-potential
Threshold
–50
–70
Time
+
–
–
+
Figure 2.2
Electrical probes placed inside and outside an axon measure its activity. (The scale is exaggerated
here. Such measurements require ultra-small electrodes, as described in this chapter.) The inside of an axon at rest
is about –60 to –70 millivolts, compared with the outside. Electrochemical changes in a neuron generate an action
potential. When sodium ions (Na) that have a positive charge rush into the cell, its interior briefly becomes positive.
This is the action potential. After the action potential, positive potassium ions (K) flow out of the axon and restore its
negative charge. (See Figure 2.3 for further explanation.)
+
–
–
+
+
–
–
+
+
–
–
+
+
+
–
–
–
–
+
+
Axon
•
Figure 2.3 The inside of an axon normally has a negative electrical charge. The
fluid surrounding an axon is normally positive.
As an action potential passes along the axon,
these charges reverse so that the interior of
the axon briefly becomes positive. This process is described in more detail in Figure 2.4.
Axon
1. In its resting state, the axon has a
negatively charged interior.
–
+
2. During an action potential, positively
charged atoms (ions) rush into the axon.
This briefly changes the electrical charge
inside the axon from negative to positive.
Simultaneously, the charge outside the
axon becomes negative.
–
–
+
–
+
+ + + +
+
–
–
–
+
+
+
+
–
–
–
–
+
+
+
+
+ + + + –
–
–
–
+
+
+
+
–
+
–
+
–
+
–
–
–
–
–
+
–
+
–
+
–
+
–
–
+
–
+
+
–
–
–
–
–
+
Action potential
–
+
•
–
Action potential
–
The axons of some neurons (such as the one pictured in Figure 2.1) are coated with a fatty layer called myelin (MY-eh-lin).
Small gaps in the myelin help nerve impulses move faster. Instead
of passing down the entire length of the axon, the action potential leaps from gap to gap, a process called saltatory conduction.
Without the added speed this allows, it would probably be
–
+
3. The action potential advances as
positive and negative charges reverse in
a moving zone of electrical activity that
sweeps down the axon.
4. After an action potential passes, positive
ions rapidly flow out of the axon to
quickly restore its negative charge. An
outward flow of additional positive ions
returns the axon to its resting state.
–
Action potential
–
Saltatory Conduction
+
–
–
+
–
+
–
–
+
–
+
–
+
–
+
–
+
+ + + + –
–
–
–
–
+
impossible to brake in time to avoid many automobile accidents
(or hit that major league fastball). When the myelin layer is damaged, a person may suffer from numbness, weakness, or paralysis.
That, in fact, is what happens in multiple sclerosis, a disease that
occurs when the immune system attacks and destroys the myelin
in a person’s body.
Brain and Behavior
51
Action potential
–
–
–
–
Ion
channels
+
+
+
+
+
–
–
–
–
Na+
–
Na+
Na+
Presynaptic
axon terminal
Resting potential
Na+
–
Axon
+
+
+
+
+
Synaptic gap
+
+
+
+
+
Synaptic
vesicle
Neurotransmitter
Na+
Action potential
+
+
K+
+
+
K+–
K+
+
+
+
+
K+
+
+
–
–
–
–
–
+
+
+
+
+
–
–
–
–
–
Axon repolarizes
2.4 The interior of an axon. The right end of the top axon is at rest.
•Thus,Figure
it has a negative charge inside. An action potential begins when ion channels
open and sodium ions (Na) rush into the axon. In this drawing, the action potential
would travel from left to right along the axon. In the lower axon, the action potential has moved to the right. After it passes, potassium ions (K) flow out of the axon.
This quickly renews the negative charge inside the axon so that it can fire again.
Sodium ions that enter the axon during an action potential are pumped out more
slowly. Removing them restores the original resting potential.
Synapses and Neurotransmitters
How does information move from one neuron to another? The nerve
impulse is primarily electrical. That’s why electrically stimulating
the brain affects behavior. To prove the point, researcher José
Delgado once entered a bullring with a cape and a radio transmitter. The bull charged. Delgado retreated. At the last instant the
speeding bull stopped short. Why? Because Delgado had placed
radio-activated electrodes (metal wires) deep within the bull’s
brain. These, in turn, stimulated “control centers” that brought
the bull to a halt (Horgan, 2005).
In contrast to the nerve impulse, communication between
neurons is chemical. The microscopic space between two neurons, over which messages pass, is called a synapse (SIN-aps)
( Figure 2.5). When an action potential reaches the tips of the
axon terminals, neurotransmitters (NOOR-oh-TRANS-miters) are released into the synaptic gap. Neurotransmitters are
chemicals that alter activity in neurons.
Let’s return to our metaphor of people standing in a line. To
be more accurate, you and the others shouldn’t be holding hands.
Instead, each person should have a squirt gun in his or her left
hand. To pass along a message, you would squirt the right hand of
the person to your left. When that person notices this “message,”
he or she would squirt the right hand of the person to the left,
and so on.
When chemical molecules cross over a synapse, they attach
to special receiving areas on the next neuron. (See Figure 2.5.)
These tiny receptor sites on the cell membrane are sensitive to neu-
•
•
Receptor site
Postsynaptic
dendrite
Figure 2.5 A highly magnified view of a synapse. Neurotransmitters are stored
•in tiny
sacs called synaptic vesicles (VES-ih-kels). When a nerve impulse reaches
the end of an axon, the vesicles move to the surface and release neurotransmitters.
These molecules cross the synaptic gap to affect the next neuron. The size of the gap
is exaggerated here; it is actually only about one millionth of an inch. Some transmitter molecules excite the next neuron and some inhibit its activity.
rotransmitters. The sites are found in large numbers on nerve cell
bodies and dendrites. Muscles and glands have receptor sites, too.
Do neurotransmitters always trigger an action potential in the
next neuron? No, but they do change the likelihood of an action
potential in the next neuron. Some transmitters excite the next
neuron (move it closer to firing). Others inhibit it (make firing
less likely).
More than 100 transmitter chemicals are found in the brain.
Some examples are acetylcholine, epinephrine, norepinephrine,
serotonin, dopamine, histamine, and various amino acids. Disturbances of any of these substances can have serious consequences.
For example, too little dopamine can cause the shaking and muscle
tremors of Parkinson’s disease. Too much dopamine may cause the
severe mental disorder known as schizophrenia (Di Forti, Lappin,
& Murray, 2007).
Many drugs imitate, duplicate, or block neurotransmitters.
For example, acetylcholine (ah-SEET-ul-KOH-leen) normally
activates muscles. Without acetylcholine, our flamenco musicians
couldn’t even move, much less perform. That’s exactly how the
Myelin A fatty layer coating some axons.
Saltatory conduction The process by which nerve impulses conducted
down the axons of neurons coated with myelin jump from gap to gap in
the myelin layer.
Synapse The microscopic space between two neurons, over which
messages pass.
Neurotransmitter Any chemical released by a neuron that alters
activity in other neurons.
Receptor sites Areas on the surface of neurons and other cells that are
sensitive to neurotransmitters or hormones.
Acetylcholine The neurotransmitter released by neurons to activate
muscles.
52
CHAPTER 2
drug curare (cue-RAH-ree) causes paralysis. By attaching to receptor sites on muscles, curare competes with acetylcholine. This
prevents acetylcholine from activating muscle cells. As a result,
a person or animal given curare cannot move — a fact known to
South American Indians of the Amazon River Basin, who use
curare as an arrow poison for hunting.
+
A
+
Neural Regulators
More subtle brain activities are affected by chemicals called neuropeptides (NOOR-oh-PEP-tides). Neuropeptides do not carry
messages directly. Instead, they regulate the activity of other neurons. By doing so, they affect memory, pain, emotion, pleasure,
moods, hunger, sexual behavior, and other basic processes. For
example, when you touch something hot, you jerk your hand away.
The messages for this action are carried by neurotransmitters. At
the same time, pain may cause the brain to release enkephalins (enKEF-ah-lins). These opiate-like neural regulators relieve pain and
stress. Related chemicals called endorphins (en-DORF-ins) are
released by the pituitary gland. Together, these chemicals reduce
the pain so that it is not too disabling (Drolet et al., 2001).
Such discoveries help explain the painkilling effect of placebos
(fake pills or injections), which raise endorphin levels (StewartWilliams, 2004). A release of endorphins also seems to underlie
“runner’s high,” masochism, acupuncture, and the euphoria sometimes associated with childbirth, painful initiation rites, and even
sport parachuting ( Janssen & Arntz, 2001). In each case, pain and
stress cause the release of endorphins. These in turn induce feelings of pleasure or euphoria similar to being “high” on morphine.
People who say they are “addicted” to running may be closer to the
truth than they realize.
bridges
To learn more about how pain can sometimes produce
feelings of relaxation or euphoria, see Chapter 4,
pages 143–144.
Ultimately, neural regulators may help explain depression,
schizophrenia, drug addiction, and other puzzling topics. For
example, women who suffer from severe premenstrual pain and
distress have unusually low endorphin levels (Straneva et al.,
2002).
Neural Networks
Let’s put together what we now know about the nerve impulse and
synaptic transmission to see how neural networks process information in our brains. Figure 2.6 shows a small part of a neural
network. Five neurons synapse with a single neuron that, in turn,
connects with three more neurons. At the point in time depicted
in the diagram, the single neuron is receiving one stronger and two
weaker excitatory messages () as well as two inhibitory ones ().
Does it fire an impulse? It depends: If enough “exciting” messages
•
–
+
+
–
Figure 2.6 A small neural network. Neuron A receives inputs from two
•weaker
and one stronger excitatory connections () and two inhibitory connections () and combines the inputs into a “decision” to launch an action potential,
which may help trigger further synaptic transmissions in other neurons.
arrive close in time, the neuron will fire — but only if it doesn’t
get too many “inhibiting” messages that push it away from its
trigger point. In this way, messages are combined before a neuron
“decides” to fire its all-or-nothing action potential.
Let’s try another metaphor. You are out shopping for new
jeans with five friends. Three of them think you should buy the
jeans (your best friend is especially positive) and two think you
shouldn’t. Because, on balance, their input is positive, you go ahead
and buy the jeans. Maybe you even tell some other friends they
should buy those jeans as well. Similarly, any single neuron in a
neural network “listens” to the neurons that synapse with it and
combines that input into an output. At any instant, a single neuron
may weigh hundreds or thousands of inputs to produce an outgoing message. After the neuron recovers from the resulting action
potential, it again combines the inputs, which may have changed in
the meantime, into another output, and another, and another.
In this way, each neuron in your brain functions as a tiny computer. Compared with the average laptop computer, a neuron is
terribly simple and slow. But multiply these events by 100 billion
neurons and 100 trillion synapses, all operating at the same time,
and you have an amazing computer — one that could easily fit
inside a shoebox.
Neuroplasticity
The neural networks in your brain constantly change. The term
neuroplasticity refers to the capacity of our brains to change in
response to experience. New synapses may form between neurons
or synaptic connections may grow stronger. ( Figure 2.6 shows
one particularly strong synapse — the large .) Other synaptic
connections may weaken and might even die. Every new experience you have is reflected in changes in your brain. For example,
rats raised in a complex environment have more synapses and longer dendrites in their brains than rats raised in a simpler environment (Kolb, Gibb, & Gorny, 2003). (See “You Can Change Your
Mind, but Can You Change Your Brain?”)
•
Brain and Behavior
53
CRIT ICA L T H I N KI N G
You Can Change Your Mind, but Can You Change Your Brain?
You can always change your mind. But does
that have anything to do with your brain?
Philosophers have debated the relationship of
the mind to the brain (and the rest of the body)
for centuries. Biopsychologists argue that every
mental event involves a brain event.
In one study, people suffering from spider phobias were treated with cognitive
behavior therapy. (For more information, see
Chapter 15, pages 505–507.)
After therapy, they could actually touch
spiders (although they might not have been
The Nervous System —
Wired for Action
ready to appear on Fear Factor). Images of
their brains revealed reduced activity in the
brain areas involved in the phobia (Paquette
et al., 2003). Not only did they change their
minds about spiders, they literally changed
their brains.
Another study focused on patients with
language difficulties caused by damage
to the left sides of their brains. To aid their
recovery, the patients were given training in
language comprehension. Not only did the
training help improve their ability to under-
stand language, but brain images revealed
that the right sides of their brains had
become more active to compensate for their
left-brain damage (Musso et al., 1999). Again,
a learning experience changed their brains.
Every time you learn something, you are
reshaping your living brain. There is even a
fancy phrase to describe what you are doing:
self-directed neuroplasticity. Just think. As
you study this psychology textbook you are
changing your mind, and your brain, about
psychology.
Central
nervous
system
Peripheral
nervous
system
Gateway Question: What are the major parts of the
nervous system?
Spinal
Somatic
Autonomic
Brain
cord
system
system
Harry and Maya are playing catch with a football. This
may look fairly simple. However, to merely toss the foot(a)
ball or catch it, a huge amount of information must be sensed, interSympathetic
Parasympathetic
preted, and directed to countless muscle fibers. As they play, Harry
system
system
and Maya’s neural circuits are ablaze with activity. Let’s explore the
(b)
“wiring diagram” that makes their game of catch possible.
As you can see in Figure 2.7, the central nervous system
Figure 2.7 Subparts of the nervous
(CNS) consists of the brain and spinal cord. The brain carries out
system. (a) Central nervous system.
(b) Peripheral nervous system.
most of the “computing” in the nervous system. Harry must use
his brain to anticipate when and where the football will arrive.
Harry’s brain communicates with the rest of his body through
general, it controls voluntary behavior, such as when Maya tosses
a large “cable” called the spinal cord. From there, messages flow
the football or Tiger Woods hits a golf ball. In contrast, the autothrough the peripheral nervous system (PNS). This intricate
nomic nervous system (ANS) serves the internal organs and
network of nerves carries information to and from the CNS.
glands. The word autonomic means “self-governing.” Activities
Are nerves the same as neurons? No. Neurons are tiny cells. You
would need a microscope to see one. Nerves are large bundles of
Neuropeptides Brain chemicals that regulate the activity of neurons,
neuron axons. You can easily see nerves without magnification.
such as enkephalins and endorphins.
Nerves in the peripheral nervous system can regrow if they are
Neuroplasticity The capacity of our brains to change in response to
damaged. The axons of most neurons in nerves outside the brain
experience.
and spinal cord are covered by a thin layer of cells called the neuriCentral nervous system (CNS) The brain and spinal cord.
lemma (NOOR-rih-LEM-ah). (Return to Figure 2.1.) The neurilemma forms a “tunnel” that damaged fibers can follow as they
Peripheral nervous system (PNS) All parts of the nervous system
outside the brain and spinal cord.
repair themselves. Because of this, patients can expect to regain
some control over severed limbs once they have been reattached.
Nerve A bundle of neuron fibers.
•
•
•
Neurilemma A layer of cells that encases many axons.
The Peripheral Nervous System
The peripheral system can be divided into two major parts (See
Figure 2.7). The somatic nervous system (SNS) carries messages to and from the sense organs and skeletal muscles. In
•
Somatic nervous system (SNS) The system of nerves linking the spinal
cord with the body and sense organs.
Autonomic nervous system (ANS) The system of nerves carrying
information to and from the internal organs and glands.
54
CHAPTER 2
governed by the autonomic nervous system are mostly “vegetative” or automatic, such as heart rate, digestion, and perspiration.
Thus, messages carried by the somatic system can make your hand
move, but they cannot cause your eyes to dilate. Likewise, messages carried by the ANS can stimulate digestion, but they cannot
help you carry out a voluntary action, such as writing a letter. If
Harry feels a flash of anger when he misses a catch, a brief burst
of activity will spread through his autonomic system.
for “fight or flight” during times of danger or high emotion. In
essence, it arouses the body for action.
The parasympathetic branch quiets the body and returns it to
a lower level of arousal. It is most active soon after an emotional
event. The parasympathetic branch also helps keep vital processes
such as heart rate, breathing, and digestion at moderate levels.
Of course, both branches of the ANS are always active. At any
given moment, their combined activity determines if your body is
more or less relaxed or aroused.
bridges
The Spinal Cord
The ANS plays a central role in our emotional lives. In fact,
without the ANS a person would feel little emotion. See
Chapter 10, pages 343–345 for more information about the
ANS and emotion.
As mentioned earlier, the spinal cord connects the brain to other
parts of the body. If you were to cut through this “cable,” you
would see columns of white matter (bundles of axons covered with
myelin). This tissue is made up of axons that eventually leave the
spinal cord to form the peripheral nervous system nerves. Thirtyone spinal nerves carry sensory and motor messages to and from
the spinal cord. In addition, 12 pairs of cranial nerves leave the
brain directly. Together, these nerves keep your entire body in
communication with your brain.
Is the spinal cord’s only function to connect the brain to the peripheral nervous system? Actually, the spinal cord can do some simple
“computing” of its own. Reflex arcs, which occur when a stimulus
provokes an automatic response, arise within the spinal cord,
without any help from the brain ( Figure 2.9). Imagine that Maya
steps on a thorn. (Yes, they’re still playing catch.) Pain is detected
in her foot by a sensory neuron (a nerve cell that carries messages
from the senses toward the CNS). Instantly, the sensory neuron
fires off a message to Maya’s spinal cord.
The ANS and SNS work together to coordinate the body’s
internal reactions to events in the world outside. For example, if
a snarling dog lunges at you, the somatic system will control your
leg muscles so that you can run. At the same time, the autonomic
system will raise your blood pressure, quicken your heart, and so
forth. The ANS can be divided into the sympathetic and parasympathetic branches. Both are related to emotional responses, such
as crying, sweating, heart rate, and other involuntary behavior
( Figure 2.8).
How do the branches of the autonomic system differ? The sympathetic branch is an “emergency” system. It prepares the body
•
Parasympathetic
•
Sympathetic
Cell body of
sensory neuron
Sensory
nerve
Constricts pupil
Stimulates tears
Stimulates salivation
Inhibits heart rate
Constricts respiration
Constricts blood vessels
Stimulates digestion
Contracts bladder
Stimulates elimination
Stimulates genitals
Dilates pupil
Inhibits tears
Inhibits salivation
Activates sweat glands
Increases heart rate
Increases respiration
Inhibits digestion
Release of adrenaline
Release of sugar from liver
Relaxes bladder
Inhibits elimination
Inhibits genitals
Ejaculation in males
Figure 2.8 Sympathetic and parasympathetic branches of the autonomic
•nervous
system. Both branches control involuntary actions. The sympathetic system
generally activates the body. The parasympathetic system generally quiets it. The
sympathetic branch relays its messages through clusters of nerve cells outside the
spinal cord.
Sensory neuron
Connector
neuron
Spinal cord
(cross section)
Motor neuron
Muscle cell responds
by contracting
2.9 A sensory-motor
•arc,Figure
or reflex, is set in motion by a
stimulus to the skin (or other part of
the body). The nerve impulse travels
to the spinal cord and then back out
to a muscle, which contracts. Such
reflexes provide an “automatic” protective device for the body.
Sensory
receptor
in skin
Stimulus to skin
Brain and Behavior
Inside the spinal cord, the sensory neuron synapses with a connector neuron (a nerve cell that links two others). The connector
neuron activates a motor neuron (a cell that carries commands from
the CNS to muscles and glands). The muscle fibers are made up
of effector cells (cells capable of producing a response). The muscle
cells contract and cause Maya’s foot to withdraw. Note that no
brain activity is required for a reflex arc to occur. Maya’s body will
react automatically to protect itself.
In reality, even a simple reflex usually triggers more complex
activity. For example, muscles of Maya’s other leg must contract
to support her as she shifts her weight. Even this can be done by
the spinal cord, but it involves many more cells and several spinal
nerves. Also, the spinal cord normally informs the brain of its
actions. As her foot pulls away from the thorn, Maya will feel the
pain and think, “Ouch, what was that?”
Perhaps you have realized how adaptive it is to have a spinal cord
capable of responding on its own. Such automatic responses leave
the brains of our football stars free to deal with more important
information — such as the location of trees, lampposts, and attractive onlookers — as they take turns making grandstand catches.
55
While peripheral nerves can regrow, a serious injury to the
brain or spinal cord is usually permanent. However, scientists
are starting to make progress repairing damaged neurons in the
CNS. For instance, they have partially repaired cut spinal cords
in rats. First they close the gap with nerve fibers from outside the
spinal cord. Then they biochemically coax the severed spinal nerve
fibers to grow through the “tunnels” (neurilemma) provided by
the implanted fibers. Within months, rats treated this way regain
some use of their hind legs (Cheng, Cao, & Olson, 1996).
Similarly, medical researchers have already begun the first
human trials in which nerve grafts will be used to repair damaged
spinal cords (Féron et al., 2005). Imagine what that could mean to
a person confined to a wheelchair. Although it is unwise to raise
false hopes, solutions to such problems are beginning to emerge.
Nevertheless, it is wise to take good care of your own CNS. That
means using seat belts when you drive, wearing a helmet if you ride
a motorcycle or bicycle, wearing protective gear for sports, and
avoiding activities that pose a risk to your head or spinal cord.
Can brain damage also be repaired? While we will be exploring
the brain itself in more detail later on in the chapter, we can, for
now, answer with an optimistic but cautious yes. (See “Repairing
Your Brain.”)
Before we go on to explore some of the research tools biopsychologists use, take some time to check out how much you’ve
learned.
KNOWL E DG E B U I L DE R
Neurons and the Nervous System
RECITE
Blend Images/Jupiter images
1. The _______________ and ____________ are the receiving areas of
a neuron where information from other neurons is accepted.
2. Nerve impulses are carried down the __________________ to the
______________ _______________________.
3. The ______________ potential becomes a(n) ______________
potential when a neuron passes the threshold for firing.
4. Neuropeptides are transmitter substances that help regulate the
activity of neurons. T or F?
5. The somatic and autonomic systems are part of the ______________
nervous system.
6. Sodium and potassium ions flow across the synapse to trigger a
nerve impulse in the receiving neuron. T or F?
7. The simplest behavior sequence is a _____________ ____________.
8. The parasympathetic nervous system is most active during times of
high emotion. T or F?
Continued
Each year spinal cord injuries rob many thousands of people of the ability to
move. Yet there is growing hope that nerve-grafting techniques may someday
make it possible for some of these people to walk again.
Sympathetic branch A branch of the ANS that arouses the body.
Parasympathetic branch A branch of the ANS that quiets the body.
Reflex arc The simplest behavior, in which a stimulus provokes an
automatic response.
Sensory neuron A nerve cell that carries information from the senses
toward the CNS.
56
CHAPTER 2
C R IT ICAL T H I N KI N G
Repairing Your Brain
Until only a few years ago, it was widely
believed that we are born with all the brain
cells we will ever have. This led to the depressing idea that we all slowly go downhill, as the
brain loses thousands of neurons every day. It
also led to limited options, such as nerve cell
transplants, for the treatment of brain damage
(Wong, Hodges, & Horsburgh, 2005). Imagine
that Bobby M. suffered partial paralysis in his
left arm due to a stroke. (A stroke occurs when
an artery in the brain becomes blocked or
bursts open. This interrupts blood flow and
causes some brain tissue to die.) What could
be done to help Bobby recover? One remedy
involves injecting immature nerve cells into
his damaged brain areas. This would allow
the new cells to link up with existing neurons in order to repair Bobby’s stroke damage (Borlongan, Sanberg, & Freeman, 1999;
Zhang, Zhang, & Chopp, 2005).
Rather than facing a steady decline, we
now know that a healthy 75-year-old brain
has just as many neurons as it did when it
was careening through life in the body of a
25-year-old. Although it is true that the brain
loses cells daily, it simultaneously grows new
neurons to replace them. This process is called
neurogenesis (noor-oh-JEN-uh-sis; the production of new brain cells) (Kempermann,
2005). Each day, thousands of new cells
originate deep within the brain, move to
the surface, and link up with other neurons
to become part of the brain’s circuitry. This is
stunning news to brain scientists, who must
now figure out what the new cells do. Most
likely they are involved in learning, memory,
and our ability to adapt to changing circumstances (Gould & Gross, 2002).
The discovery of neurogenesis in adult
brains has raised hope that new treatments can be found for some types of brain
damage. For example, an approach called
constraint-induced movement therapy could
be used to speed Bobby M.’s recovery. In
this case, Bobby’s good right arm would be
restrained, forcing his impaired left arm to
be more active, which would increase neurogenesis in the damaged part of his brain
(Taub, 2004). In another approach, drugs that
speed up neurogenesis could be injected into
REFLECT
Critical Thinking
9. What effect would you expect a drug to have if it blocked passage of
neurotransmitters across the synapse?
Relate
To cope with all the technical terms in this section, think of neurons as
strange little creatures. How do they act? What excites them? How do they
communicate? To remember the functions of major branches of the nervous system, think about what you couldn’t do if each part were missing.
the damaged area of Bobby’s brain (Zhang,
Zhang, & Chopp, 2005). Such techniques are
beginning to offer new hope for people suffering from a variety of other disabilities, such
as blindness and Parkinson’s disease (Brinton
& Wang, 2006; Burke et al., 2007).
But don’t these treatments assume that
Bobby’s brain is still capable of neurogenesis?
What if it isn’t? Brilliant! Although a stroke
most likely doesn’t damage the brain’s ability
to repair itself, it is quite possible that other
brain disorders do arise from impaired neurogenesis (Thompson et al., 2008). In fact, that is
exactly the theory proposed by neuroscientists
Carla Toro and Bill Deakin to explain the serious
mental disorder schizophrenia (Toro & Deakin,
2007). The brains of schizophrenic persons are
usually smaller than normal, indicating that
they have fewer neurons. Toro and Deakin’s
idea is that the schizophrenic brain may be
unable to continually create new neurons to
replace old ones that have died. If they are
right, new therapies to promote neurogenesis
may hold the key to treating schizophrenia,
one of the most devastating mental illnesses.
brain to the control of particular cognitive or behavioral functions, such as being able to recognize faces or move your hands.
That is, they try to learn where functions are localized (located) in
the brain. Many techniques have been developed to help identify
brain structures and the functions they control.
Mapping Brain Structure
Anatomists have learned much about brain structure by dissecting
(cutting apart) autopsied human and animal brains and examining them under a microscope. Dissection reveals that the brain
is made up of many anatomically distinct areas or “parts.” Less
intrusive newer methods, such as the CT scan and the MRI scan,
can be used to map brain structures in living brains.
Answers: 1. dendrites, soma 2. axon, axon terminals 3. resting, action
4. T 5. peripheral 6. F 7. reflex arc 8. F 9. Such a drug could have wideranging effects. If the drug blocked excitatory synapses, it would depress
brain activity. If it blocked inhibitory messages, it would act as a powerful
stimulant.
CT Scan
Research Methods — Charting
the Brain’s Inner Realms
Gateway Question: How is the brain studied?
Biopsychology is the study of how biological processes, and especially those of the nervous system, relate to behavior. In their
research, many biopsychologists try to relate specific parts of the
Computerized scanning equipment has revolutionized the study
of brain structures and made it easier to identify brain diseases
and injuries. At best, conventional X-rays produce only shadowy
images of the brain. Computed tomographic (CT) scanning is
a specialized type of X-ray that does a much better job of making
the brain visible. In a CT scan, X-rays taken from a number of
different angles are collected by a computer and formed into an
image of the brain. A CT scan can reveal the location of strokes,
injuries, tumors, and other brain disorders.
57
Brain and Behavior
recovery that has been miraculous by any measure, she even went
on to appear before the U. S. Congress.
Instead of relying on clinical studies, researchers have learned
much from electrical stimulation of the brain (ESB) ( Figure 2.11). For example, the surface of the brain can be “turned on”
by stimulating it with a mild electrical current delivered through a
thin insulated wire called an electrode. When this is done during
brain surgery, the patient can describe what effect the stimulation
had. (The brain has no pain receptors, so surgery can be done while
a patient is awake. Only local painkillers are used for the scalp and
skull.) (Any volunteers?) Even structures below the surface of the
brain can be activated by lowering a stimulating electrode, insulated
except at the tip, into a target area inside the brain. ESB can call
forth behavior with astonishing power. Instantly, it can bring about
aggression, alertness, escape, eating, drinking, sleeping, movement,
euphoria, memories, speech, tears, and more.
Could ESB be used to control a person against his or her will?
It might seem that ESB could be used to control a person like a
robot. But the details of emotions and behaviors elicited by ESB
are modified by personality and circumstances. Sci-fi movies to
the contrary, it would be impossible for a ruthless dictator to
enslave people by “radio controlling” their brains.
An alternate approach is ablation (ab-LAY-shun: surgical
removal) of parts of the brain. (See Figure 2.11.) When ablation
CNRI/Photo Researchers, Inc.
•
Figure 2.10 A colored MRI scan of the brain reveals many details. Can you
•identify
any brain regions?
MRI Scan
Magnetic resonance imaging (MRI) uses a very strong magnetic
field, rather than X-rays, to produce an image of the body’s interior. During an MRI scan, the body is placed inside a magnetic
field. Processing by a computer then creates a three-dimensional
model of the brain or body. Any two-dimensional plane, or slice,
of the body can be selected and displayed as an image on a computer screen. MRI scans produce more detailed images than are
possible with CT scans, allowing us to peer into the living brain
almost as if it were transparent ( Figure 2.10).
•
Stimulation
electrode
•
Deep-lesioning
electrode
Surgical
ablation
Exploring Brain Function
How does the brain allow us to think, feel, perceive, or act? To answer
questions like these, we must localize function by linking these
psychological or behavioral capacities with particular brain structures. In many instances, this has been done through clinical case
studies. Such studies examine changes in personality, behavior, or
sensory capacity caused by brain diseases or injuries. If damage to
a particular part of the brain consistently leads to a particular loss
of function, then we say the function is localized in that structure.
Presumably, that part of the brain controls the same function in
all of us.
Consider, for example, the story of Kate Adamson (Adamson,
2004). At the age of 33, she had a stroke that caused catastrophic
damage to her brainstem. This event left her with locked-in syndrome: One moment she was fine, and the next she was totally
paralyzed, trapped in her own body and barely able to breathe. As
you can see, this clinical case suggests that our brainstems play a
role in the control of vital life functions, such as movement and
breathing.
But what happened to Kate? Oh, yes. Unable to move a muscle,
but still fully awake and aware, Kate thought she was going to die.
Her doctors, who thought she was brain dead (Laureys & Boly,
2007), did not administer painkillers as they inserted breathing
and feeding tubes down her throat. However, in time Kate discovered that she could communicate by blinking her eyes. After a
2.11 The functions of
•brainFigure
structures are explored by selectively
activating or removing them. Brain research
is often based on electrical stimulation, but
chemical stimulation is also used at times.
Neurogenesis The production of new brain cells.
Computed tomographic (CT) scanning A computer-enhanced X-ray
image of the brain or body.
Magnetic resonance imaging (MRI) A three-dimensional image of
the brain or body, based on its response to a magnetic field.
Localization of function The research strategy of linking specific
structures in the brain with specific psychological or behavioral
functions.
Clinical case study A detailed investigation of a single person,
especially one suffering from some injury or disease.
Electrical stimulation of the brain (ESB) Direct electrical stimulation
and activation of brain tissue.
Electrode Any device (such as a wire, needle, or metal plate) used to
electrically stimulate or destroy nerve tissue or to record its activity.
Ablation Surgical removal of tissue.
CHAPTER 2
causes changes in behavior or sensory capacity, we also gain insight
into the purpose of the missing “part.” By using deep lesioning
(LEE-zhun-ing), structures below the surface of the brain can also
be removed. A strong electric current can be used to destroy a small
amount of brain tissue when delivered via an electrode lowered into
a target area inside the brain. (See Figure 2.11.) Again, changes in
behavior give clues to the function of the affected area.
By using ESB, ablation, and deep lesioning, researchers are
creating a three-dimensional brain map. This “atlas” shows the
sensory, motor, and emotional responses that can be elicited from
various parts of the brain. It promises to be a valuable guide for
medical treatment, as well as for exploring the brain (Kalat, 2007;
Yoshida, 1993).
To find out what individual neurons are doing, we need to do
a microelectrode recording. A microelectrode is an extremely thin
glass tube filled with a salty fluid. The tip of a microelectrode is
small enough to detect the electrical activity of a single neuron.
Watching the action potentials of just one neuron provides a fascinating glimpse into the true origins of behavior. (The action potential shown in Figure 2.2 was recorded with a microelectrode.)
Are any less invasive techniques available for studying brain function? Yes, several techniques allow us to observe the activity of
parts of the brain without doing any damage at all. These include
the EEG, PET scan, and fMRI. Such techniques allow biopsychologists to pinpoint areas in the brain responsible for thoughts,
feelings, and actions.
example, Chapter 6, page 186, explains how changes in brain waves
help define various stages of sleep.)
PET Scan
A newer technology, called positron emission tomography (PET),
provides much more detailed images of activity both near the surface and below the surface of the brain. A PET scan detects positrons
(subatomic particles) emitted by weakly radioactive glucose (sugar)
as it is consumed by the brain. Because the brain runs on glucose, a
PET scan shows which areas are using more energy. Higher energy
use corresponds with higher activity. Thus, by placing positron
detectors around the head and sending data to a computer, it is possible to create a moving, color picture of changes in brain activity.
As you can see in Figure 2.13, PET scans reveal that very specific
brain areas are active when you see, hear, speak, or think.
•
•
bridges
PET scans suggest that different patterns of brain activity
accompany major psychological disorders, such as depression
or schizophrenia. See Chapter 14, pages 473–475.
•
More active brains are good, right? Surprisingly, although we
might assume that smart brains are hardworking brains, the reverse
appears to be true. Using PET scans, psychologist Richard Haier
and his colleagues found that the brains of people who perform
well on a difficult reasoning test consume less energy than those
of poor performers (Haier et al., 1988) ( Figure 2.14). Haier
believes this shows that intelligence is related to brain efficiency:
Less efficient brains work harder and still accomplish less (Haier,
White, & Alkire, 2003). We’ve all had days like that!
Is it true that most people use only 10 percent of their brain capacity? This is one of the lasting myths about the brain. Brain scans
show that all parts of the brain are active during waking hours.
Obviously, some people make better use of their innate brainpower
than others do. Nevertheless, there are no great hidden or untapped
reserves of mental capacity in a normally functioning brain.
EEG
•
Electroencephalography (ee-LEK-tro-in-SEF-ah-LOG-ruh-fee) measures the waves of electrical activity produced near the surface of the
brain. Small disk-shaped metal plates are placed on a person’s scalp.
Electrical impulses from the brain are detected by these electrodes
and sent to an electroencephalograph (EEG). The EEG amplifies
these very weak signals (brain waves) and records them on a moving sheet of paper or a computer screen ( Figure 2.12). Various
brain-wave patterns can identify the presence of tumors, epilepsy,
and other diseases. The EEG also reveals changes in brain activity
during sleep, daydreaming, hypnosis, and other mental states. (For
AJPhoto/Photo Researchers, Inc.
•
• Figure 2.12 An EEG recording.
Seeing
Hearing
Speaking
Thinking
WDCN/Univ. College London/Photo Researchers, Inc.
58
Figure 2.13 Colored PET scans reveal different patterns of brain activation
•when
we engage in different tasks.
59
Brain and Behavior
A functional MRI (f MRI) uses MRI technology
to make brain activity visible. Like PET scans, functional MRIs also provide images of activity throughout the brain. For example, if we scanned Carlos
Santana while he played his guitar, areas of his brain
that control his hands would be highlighted in an
fMRI image.
Psychiatrist Daniel Langleben and his colleagues
have even used fMRI images to tell if a person is
lying (Langleben et al., 2005). As Figure 2.15
shows, the front of the brain is more active when a
person is lying, rather than telling the truth. This
Figure 2.14 In the images you see here, red, orange, and yellow indicate high consumption
may occur because it takes extra effort to lie and of glucose; green, blue, and pink show areas of low glucose use. The PET scan of the brain on the left
the resulting extra brain activity is detected with shows that a man who solved 11 out of 36 reasoning problems burned more glucose than the man on
fMRI. Eventually, fMRI may help us distinguish the right, who solved 33.
between lies, false statements made with the intention to deceive, and confabulations, which are false claims made
by persons who believe they are telling the truth (Hirstein, 2005;
Langleben, Dattilio, & Gutheil, 2006). Clearly, it is just a matter
of time until even brighter beacons are flashed into the shadowy
inner world of thought.
•
•
Left side
K N O WL E D GE B U I L D E R
Brain Research
Lie Activation
Truth Activation
RECITE
1. Which of the following research techniques has the most in common with clinical studies of the effects of brain injuries?
a. EEG recording
b. deep lesioning
c. microelectrode recording
d. PET scan
2. CT scans cannot determine which part of your brain plays a role in
speech because CT scans
a. use X-rays
b. reveal brain structure, not brain activity
c. reveal brain activity, not brain structure
d. use magnetic fields
3. _________________ links brain structures to brain functions.
4. People only use 10 percent of their brain capacity. T or F?
REFLECT
Critical Thinking
5. Deep lesioning is used to ablate an area in the hypothalamus of a
rat. After the operation, the rat seems to lose interest in food and
eating. Why would it be a mistake to automatically conclude that the
ablated area is a “hunger center”?
Relate
You suspect that a certain part of the brain is related to risk-taking. How
could you use clinical studies, ablation, deep lesioning, and ESB to study
the structure? You want to know which areas of the brain’s surface are
most active when a person sees a face. What methods will you use?
Anterior
•
Daniel Langleben, University of Pennsylvania
Right side
Figure 2.15
Participants were asked to tell the truth or to lie while fMRI
images of their brains were taken. When compared with telling the truth (shown in
blue), areas toward the front of the brain were active during lying (shown in red).
(Adapted from Langleben et al., 2005.)
The Cerebral Cortex — My, What
a Big Brain You Have!
Gateway Question: Why is the human cerebral cortex so important,
and what are its parts?
In many ways we are pretty unimpressive creatures. Animals
surpass humans in almost every category of strength, speed, and
sensory sensitivity. However, we do excel in intelligence.
Deep lesioning Removal of tissue within the brain by use of an electrode.
Electroencephalograph (EEG) A device that detects, amplifies, and
records electrical activity in the brain.
PET scan Positron emission tomography; a computer-generated image
of brain activity based on glucose consumption in the brain.
Functional MRI (fMRI) Functional magnetic resonance imaging that
records brain activity.
Richard Haier, University of California, Irvine
fMRI
Answers: 1. b 2. b 3. Localization of function 4. F 5. Because other factors
might explain the apparent loss of appetite. For example, the taste or smell
of food might be affected, or the rat might simply have difficulty swallowing. It is also possible that hunger originates elsewhere in the brain and the
ablated area merely relays messages that cause the rat to eat.
60
CHAPTER 2
Cortex
Cerebrum
Cerebellum
Neocortex
Olfactory lobe
Although the cortex is only 3 millimeters thick (one tenth of an inch), it
contains 70 percent of the neurons in
the central nervous system. It is largely
responsible for our ability to use language,
make tools, acquire complex skills, and
live in complex social groups (Gibson,
2002). Without the cortex, we humans
wouldn’t be much smarter than toads.
Cerebral Hemispheres
Fish Brain
The cortex is composed of two sides, or
cerebral hemispheres (half-globes), conCerebrum
nected by a thick band of fibers called the
corpus callosum (KORE-pus kah-LOHsum) ( Figure 2.17). The left side of the
brain mainly controls the right side of the
Cerebellum body. Likewise, the right brain mainly
Human Brain
Olfactory lobe
Cerebrum
controls left body areas. When our friend
Marge had a stroke, her right hemisphere
Reptile Brain
suffered damage. In Marge’s case, the
Figure 2.16
stroke caused some paralysis and loss of
sensation on the left side of her body.
Damage to one hemisphere may also cause a curious problem
Does that mean humans have the largest brains? Surpriscalled spatial neglect. A patient with right hemisphere damage may
ingly, no. Elephant brains weigh 13 pounds, and whale brains,
pay no attention to the left side of visual space ( Figure 2.18).
19 pounds. At 3 pounds, the human brain seems puny — until
Often, the patient will not eat food on the left side of a plate.
we compare brain weight to body weight. We then find that
Some even refuse to acknowledge a paralyzed left arm as their
an elephant’s brain is 1/1,000 of its weight; the ratio for sperm
own (Hirstein, 2005). If you point to the “alien” arm, the patient
whales is 1 to 10,000. The ratio for humans is 1 to 60. If someone
is likely to say, “Oh, that’s not my arm. It must belong to someone
tells you that you have a “whale of a brain” be sure to find out if
else.” (To learn more about strokes, see “A Stroke of Bad Luck.”)
they mean size or ratio!
So having a larger brain doesn’t necessarily make a person smarter?
That’s right. While a small positive correlation exists between
Hemispheric Specialization
intelligence and brain size, overall size alone does not determine
In 1981, Roger Sperry (1914–1994) won a Nobel Prize for his
human intelligence ( Johnson et al., 2008; Witelson, Beresh, &
remarkable discovery that the right and left brain hemispheres
Kigar, 2006). In fact, many parts of your brain are surprisingly
perform differently on tests of language, perception, music, and
similar to corresponding brain areas in lower animals, such as
other capabilities.
lizards. It is your larger cerebral (seh-REE-brel or ser-EH-brel)
Corpus
Cerebral
cortex that sets you apart.
callosum
cortex
The cerebral cortex, which looks a little like a giant, wrinkled
walnut, consists of the two large hemispheres that cover the upper
part of the brain. The two hemispheres are divided into smaller
areas known as lobes. Parts of various lobes are responsible for the
ability to see, hear, move, think, and speak. Thus, a map of the
cerebral cortex is in some ways like a map of human behavior, as
we shall see.
The cerebral cortex covers most of the brain with a mantle of
gray matter (spongy tissue made up mostly of cell bodies). The cortex in lower animals is small and smooth. In humans it is twisted
and folded, and it is the largest brain structure ( Figure 2.16).
The fact that humans are more intelligent than other animals is
related to this corticalization (KORE-tih-kal-ih-ZAY-shun), or
Figure 2.17
increase in the size and wrinkling of the cortex.
Neocortex
Cerebellum
•
•
•
•
•
Brain and Behavior
61
T HE CLI N I CA L FI LE
A Stroke of Bad Luck
One morning Bryan Kolb lost his left hand.
Up early to feed his cat, he could not see his
hand, or anything else to his upper left side.
Kolb, a Canadian neuroscientist, instantly realized that he had suffered a right hemisphere
stroke. (Remember, a stroke occurs when an
artery carrying blood in the brain bleeds or
becomes blocked, causing some brain tissue
to die.) He drove to the hospital where he
argued with the doctors about his own diagnosis. He was right, of course! He eventually
resumed his career and even wrote a fascinating account of his own case (Kolb, 1990).
Model
Neurological soft signs, as they are
called, include clumsiness, an awkward gait,
poor hand–eye coordination, and other
problems with perception or fine muscle
control (Stuss & Levine, 2002). These telltale
signs are “soft” in the sense that they aren’t
direct tests of the brain, like a CT scan or MRI
scan. Bryan Kolb initially diagnosed himself
entirely with soft signs. Likewise, soft signs
help psychologists diagnose problems ranging from childhood learning disorders to
full-blown psychosis (Ward, 2006).
Patient’s copy
1
f
Le
2
10
9
tv
iel
d
11
12
Strokes and other brain injuries can hit
like a thunderbolt. Almost instantly, victims
realize that something is wrong. You would,
too, if you suddenly found that you couldn’t
move, or feel parts of your body, or see, or
speak. However, some brain injuries are not
so obvious. Many involve less dramatic, but
equally disabling, changes in personality,
thinking, judgment, or emotions (Banich,
2004; Borod et al., 2002). Although major
brain injuries are easy enough to spot, psychologists also look for more subtle signs
that the brain is not working properly.
3
f
al
l field Right visu
isu
a
4
8
7
6
5
Left eye
Right eye
Optic nerve
Corpus callosum
(cut)
Optic chiasm
(crossover)
Lateral geniculate
body of thalamus
Optic
radiation
Occipital
lobe
Figure 2.18 Spatial neglect. A patient with right-hemisphere damage was
•asked
to copy three model drawings. Notice the obvious neglect of the left side
2.19 Basic nerve pathways of vision. Notice that the left portion of
•eachFigure
eye connects only to the left half of the brain; likewise, the right portion of
in his drawings. Similar instances of neglect occur in many patients with righthemisphere damage. (From Left Brain, Right Brain, Fifth Edition by Sally P. Springer & Georg
each eye connects to the right brain. When the corpus callosum is cut, a “split brain”
results. Then visual information can be sent to just one hemisphere by flashing it in
the right or left visual field as the person stares straight ahead.
Deutsch. © 1981, 1985, 1989, 1993, 1998 by Sally P. Springer and Georg Deutsch. Used with permission of W. H. Freeman and Company.)
How is it possible to test only one side of the brain? One way is to
work with people who’ve had a “split-brain” operation. In this
rare type of surgery, the corpus callosum is cut to control severe
epilepsy. The result is essentially a person with two brains in one
body. After the surgery it is possible to send information to one
hemisphere or the other ( Figure 2.19).
•
Cerebral cortex The outer layer of the brain.
Corticalization An increase in the relative size of the cerebral cortex.
Neurological soft signs Subtle behavioral signs of brain dysfunction,
including clumsiness, an awkward gait, poor hand–eye coordination,
and other perceptual and motor problems.
“Split-brain” operation Cutting the corpus callosum.
62
CHAPTER 2
•
Figure 2.20 A circle is flashed to the left
brain of a split-brain patient and he is asked what
he saw. He easily replies, “A circle.” He can also
pick out the circle by merely touching shapes
with his right hand, out of sight behind a screen.
However, his left hand can’t identify the circle. If
a triangle is flashed to the patient’s right brain,
he can’t say what he saw (speech is controlled
by the left hemisphere). He also can’t identify
the triangle by touch with the right hand. Now,
however, the left hand has no difficulty picking
out the triangle. In other tests, the hemispheres
reveal distinct skills, as listed above the drawing.
I see
nothing.
I see a
circle.
Left Hemisphere
Right Hemisphere
“Split Brains”
After the right and left brain are separated, each hemisphere will
have its own separate perceptions, concepts, and impulses to act.
How does a split-brain person act after the operation? Having two
“brains” in one body can create some interesting dilemmas. When
one split-brain patient dressed himself, he sometimes pulled his
pants up with one hand (that side of his brain wanted to get
dressed . . .) and down with the other (. . . while this side didn’t).
Once, he grabbed his wife with his left hand and shook her violently. Gallantly, his right hand came to her aid and grabbed the
aggressive left hand (Gazzaniga, 1970). However, such conflicts
are actually rare. That’s because both halves of the brain normally
have about the same experience at the same time. Also, if a conflict
arises, one hemisphere usually overrides the other.
Split-brain effects are easiest to see in specialized testing. For
example, we could flash a dollar sign to the right brain and a question mark to the left brain of a patient named Tom. ( Figure
2.19 shows how this is possible.) Next, Tom is asked to draw what
he saw, using his left hand, out of sight. Tom’s left hand draws a
dollar sign. If Tom is then asked to point with his right hand to a
picture of what his hidden left hand drew, he will point to a question mark (Sperry, 1968). In short, for the split-brain person, one
hemisphere may not know what is happening in the other. This
has to be the ultimate case of the “right hand not knowing what
the left hand is doing”! Figure 2.20 provides another example of
split-brain testing.
•
tions, the right hemisphere must use nonverbal responses, such as
pointing at objects ( Figure 2.21).
Although it is poor at producing language, the right brain is
especially good at perceptual skills, such as recognizing patterns,
faces, and melodies; putting together a puzzle; or drawing a picture. It is also helps you express emotions and detect the emotions
that other people are feeling (Borod et al., 2002; Stuss & Alexander, 2000).
Even though the right hemisphere is nearly “speechless,” it is
superior at some aspects of understanding language. If the right
side of the brain is damaged, people lose their ability to understand jokes, irony, sarcasm, implications, and other nuances of
language. Basically, the right hemisphere helps us see the overall
context in which something is said (Beeman & Chiarello, 1998).
•
Left hemisphere
Right hemisphere
DETAILS
OVERALL PATTERN
“A bunch of Ds”
D
D
D
D
D
DDDDD
“The letter L”
A stitch in time
saves nine.
“A small effort now
saves time later.”
“It’s about sewing.”
Right Brain/Left Brain
Earlier it was stated that the hemispheres differ in abilities; in what
ways are they different? The brain divides its work in interesting ways.
Roughly 95 percent of us use our left brain for language (speaking,
writing, and understanding). In addition, the left hemisphere is
superior at math, judging time and rhythm, and coordinating the
order of complex movements, such as those needed for speech.
In contrast, the right hemisphere can produce only the simplest
language and numbers. Working with the right brain is like talking
to a child who can say only a dozen words or so. To answer ques-
“Dots and blobs”
“A dog”
Figure 2.21 The left and right brain have different information processing
•styles.
The right brain gets the big pattern; the left focuses on small details.
Ronald C. James
•
Brain and Behavior
63
One Brain, Two Styles
The Frontal Lobes
In general, the left hemisphere is mainly involved with analysis
(breaking information into parts). It also processes information
sequentially (in order, one item after the next). The right hemisphere appears to process information simultaneously and holistically (all at once) (Springer & Deutsch, 1998).
To summarize further, you could say that the right hemisphere
is better at assembling pieces of the world into a coherent picture;
it sees overall patterns and general connections. The left brain
focuses on small details. (See Figure 2.21.) The right brain sees
the wide-angle view; the left zooms in on specifics. The focus
of the left brain is local, the right is global (Hübner & Volberg,
2005).
Do people normally do puzzles or draw pictures with just the right
hemisphere? Do they do other things with only the left? Numerous
books have been written about how to use the right brain to manage, teach, draw, ride horses, learn, and even make love (Clark,
Boutros, & Mendez, 2005). But such books drastically oversimplify right-brain and left-brain differences. People normally use
both sides of the brain at all times. It’s true that some tasks may
make more use of one hemisphere or the other. But in most “real
world” activities, the hemispheres share the work. Each does the
parts it does best and shares information with the other side.
A smart brain is one that grasps both the details and the overall
picture at the same time. For instance, during a concert a flamenco
guitarist will use his left brain to judge time and rhythm and coordinate the order of his hand movements. At the same time, he will
use his right brain to recognize and organize melodies.
The frontal lobes are associated with higher mental abilities and
play a role in your sense of self. This area is also responsible for the
control of movement. Specifically, an arch of tissue at the rear of the
frontal lobes, called the primary motor area (or primary motor
cortex), directs the body’s muscles. If this area is stimulated with
an electrical current, various parts of the body will twitch or move.
The drawing wrapped around the motor cortex in Figure 2.23
is out of proportion because it reflects the dexterity of body areas,
not their size. The hands, for example, get more area than the feet.
(See Figure 2.23.) If you’ve ever wondered why your hands are
more skilled or agile than your feet, it’s partly because more motor
cortex is devoted to the hands. Incidentally, due to neuroplasticity,
learning and experience can alter these “motor maps.” For instance,
violin, viola, and cello players have larger “hand maps” in the cortex
(Hashimoto et al., 2004).
Motor cortex is one brain area that contains mirror neurons.
These are neurons that become active when we perform an action
and when we merely observe someone else carrying out the same
action. (For more information about mirror neurons, see “Mirror,
Mirror in the Brain.”)
The rest of the frontal lobes are often referred to as frontal
association areas. Only a small portion of the cerebral cortex (the
primary areas) directly controls the body or receives information
from the senses. All the surrounding areas, which are called association areas (or association cortex), combine and process information. For example, if you see a rose, association areas will help
you connect your primary sensory impressions with memories,
so that you can recognize the rose and name it. Some association
areas also contribute to higher mental abilities, such as language.
For example, a person with damage to association areas in the left
hemisphere may suffer aphasia (ah-FAZE-yah: an impaired ability
to use language).
One type of aphasia is related to Broca’s (BRO-cahs) area, a
“speech center” that is part of the left frontal association area (for
5 percent of all people, the area is part of the right frontal association area). Damage to Broca’s area causes motor (or expressive)
•
Lobes of the Cerebral Cortex
Each of the two hemispheres of the cerebral cortex can be divided
into several smaller lobes. Some of the lobes of the cerebral cortex
are defined by larger fissures on the surface of the cortex. Others
are regarded as separate areas because their functions are quite different ( Figure 2.22).
•
Frontal lobe
(sense of self, motor control,
and higher mental abilities
such as reasoning and planning)
Parietal lobe
(sensation such as
touch, temperature,
and pressure)
•
•
Lobes of the cerebral cortex Areas on the cortex bordered by major
fissures or defined by their functions.
Frontal lobes A brain area associated with movement, the sense of self,
and higher mental functions.
Occipital
lobe
(vision)
Temporal lobe
(hearing and
language)
• Figure 2.22
Primary motor area (primary motor cortex) A brain area associated
with control of movement.
Mirror neuron A neuron that becomes active when a motor action is
carried out and when another organism is observed carrying out the
same action.
Cerebellum
(posture, coordination,
muscle tone, and memory
of skills and habits)
Association area (association cortex) All areas of the cerebral cortex
that are not primarily sensory or motor in function.
Aphasia A speech disturbance resulting from brain damage.
Broca’s area A language area related to grammar and pronunciation.
64
CHAPTER 2
Primary Motor
s
r
ge
Trun
k
Trunk
Neck
Head
Shoulder
Arm
Elbow
arm
Forreist
W nd
Hattle
Li ng le
Ri idd x
M de
In
Jaw
Shoulder
Elbow
at
Saliv
Voc
alization
Lips
Wrist
Hand
le
Litting le
R idd x
M de b
In humck
T e
N
Br
Eye ow
Fac lid an
e
d
Primary Somatosensory
ip
H
Knee
Ankle
Toes
T
Ey hum
rs
No e b
ge
Fin
Fac se
e
Up
per
lip
Lips
Lowe
r lip
Teeth, gums, an
d jaw
Tongue
al
x
min
ryn
Pha -abdo
a
Intr ans
org
Fin
eye
ba
ll
Left
hemisphere
e
Tongu
M Swa
ll
a
ion sticatioowing
n
Left
hemisphere
Temporal lobe
Temporal lobe
Primary
somatosensory
area
Primary motor area
•
Figure 2.23 The lobes of the
Prefrontal area
cerebral cortex and the primary sensory,
motor, visual, and auditory areas on each.
Broca’s area
The top diagrams show (in cross section) the
relative amounts of cortex “assigned” to the
sensory and motor control of various parts
of the body. (Each cross section, or “slice,” of
Primary auditory area
the cortex has been turned 90 degrees so
that you see it as it would appear from the
back of the brain.)
p
Hi eg
L
Foot
Toes
Genitalia
Primary
visual area
Wernicke’s
area
Cerebellum
Pons
Medulla
aphasia, a great difficulty in speaking or writing (Ward, 2006).
Generally, the person knows what she or he wants to say but can’t
seem to fluently utter the words (Geschwind, 1979). Typically, a
patient’s grammar and pronunciation are poor and speech is slow
and labored. For example, the person may say “bife” for bike,
“seep” for sleep, or “zokaid” for zodiac.
The very front of the frontal association region is known
as the prefrontal area (or prefrontal cortex). This part of the
brain is related to more complex behaviors. If the frontal lobes
are damaged, a patient’s personality and emotional life may
change dramatically. Remember Phineas Gage, the railroad foreman described in Chapter 1? It’s likely that Gage’s personality
changed after he suffered brain damage because the prefrontal
cortex generates our sense of self, including an awareness of our
current emotional state (Moran et al., 2006; Kawasaki et al.,
2005).
Reasoning or planning may also be affected (Goel & Dolan,
2004). Patients with damage to the frontal lobes often get “stuck”
on mental tasks and repeat the same wrong answers over and over
Spinal cord
(Stuss & Knight, 2002). PET scans suggest that much of what we
call intelligence is related to increased activity in the frontal areas
of the cortex (Duncan, 2005). Sadly, drug abuse can damage this
important area of the brain (Liu et al., 1998).
The Parietal Lobes
Bodily sensations register in the parietal (puh-RYE-ih-tal) lobes,
located just above the occipital lobes. Touch, temperature, pressure, and other somatic sensations flow into the primary somatosensory (SO-mat-oh-SEN-so-ree) area (or primary somatosensory cortex) of the parietal lobes. Again we find that the map
of bodily sensations is distorted. In the case of somatosensory
cortex, the drawing in Figure 2.23 reflects the sensitivity of body
areas, not their size. For example, the lips are large in the drawing because of their great sensitivity, whereas the back and trunk,
which are less sensitive, are much smaller. Notice that the hands
are also large in the map of body sensitivity — which is obviously
an aid to musicians, typists, watchmakers, massage therapists, lovers, and brain surgeons.
•
Brain and Behavior
65
CRIT ICA L T H I N KI N G
Italian researchers had just recorded an
increase in the activity of a single neuron in
the motor cortex of a monkey as it reached for
food. A few seconds later, one of the researchers happened to reach for a snack of his own.
The same neuron obligingly responded as if
the monkey had reached for the food itself.
Unexpectedly, a neuron involved in controlling a particular motor movement was also
activated when the monkey merely observed
that same motor movement in someone else.
Just like that, the Italians discovered mirror
neurons (Rizzolatti, Fogassi, & Gallese, 2006).
Because they mirror actions performed by
others, such neurons may explain how we
can intuitively understand other people’s
behavior. They may also underlie our ability
to learn new skills by imitation (Rizzolatti &
Craighero, 2004).
The discovery of mirror neurons has triggered a flood of interest. Recently, researchers have confirmed that mirror neurons
are found in various areas of the brain and
appear to exist in the human brain as well
(Bertenthal & Longo, 2007). In addition, neuroscientists speculate that newborn humans
(and monkeys) are able to imitate others
because networks of mirror neurons are
activated when an infant watches someone
perform an action. Then the same mirror
network can be used to perform that action
(Lepage & Théret, 2007). Similarly, human
empathy (the ability to identify with another
person’s experiences and feelings) may arise
from activation of mirror neurons (de C.
Hamilton, 2008).
Mirror neurons may even partially explain
autism spectrum disorders. In early childhood, children with autism begin to suffer
from an impaired ability to interact and
communicate with other people. Restricted
and repetitive behavior such as head banging is also common. According to the “broken mirrors” hypothesis, autism may arise
in infants whose mirror neuron system has
been damaged by genetic defects or environmental risk factors (Ramachandran &
Oberman, 2006). This explanation is attractive because autism’s primary features of
impaired communication and social interaction appear to be related to the role that
mirror neurons play in reflecting the actions
and words of others.
To date, these are just hypotheses that
await empirical confirmation. More importantly, such possibilities have not yet led to
any new therapies for autism. Nevertheless,
the possibilities are exciting.
China Photos/Getty Images
Mirror, Mirror in the Brain
The intense social isolation of autism spectrum
disorder may arise because of damage to mirror
neurons distributed throughout the brain.
The Temporal Lobes
The Occipital Lobes
The temporal lobes are located on each side of the brain. Auditory information projects directly to the primary auditory area,
making it the main site where hearing first registers. If we did a
PET scan of your brain while you listened to your favorite MP3,
your primary auditory area would be the first to light up, followed
by association areas in your temporal lobes. Likewise, if we could
electrically stimulate the primary auditory area of your temporal
lobe, you would “hear” a series of sound sensations.
An association area, called Wernicke’s (VER-nick-ees) area
(see Figure 2.23), lies on the left temporal lobe (again, for
5 percent of all people, the area is on the right temporal lobe).
Wernicke’s area also functions as a language site. If it is damaged,
the result is a receptive (or fluent) aphasia. Although the person can
hear speech, he or she has difficulty understanding the meaning
of words. Thus, when shown a picture of a chair, someone with
Broca’s aphasia might say “tssair.” In contrast, a Wernicke’s patient
might fluently, but incorrectly, identify the photo as “truck”
(Ward, 2006).
At the back of the brain, we find the occipital (awk-SIP-ih-tal)
lobes, the area of the cortex concerned with vision. Patients with
tumors (cell growths that interfere with brain activity) in the
•
Prefrontal area (prefrontal cortex) The very front of the frontal lobes;
involved in sense of self, reasoning, and planning.
Parietal lobes Area of the brain where body sensations register.
Primary somatosensory area (primary somatosensory cortex)
A receiving area for body sensations.
Temporal lobes Areas on each side of the brain where hearing
registers in the brain.
Primary auditory area Part of the temporal lobe where auditory
information is first registered.
Wernicke’s area A temporal lobe brain area related to language
comprehension.
Occipital lobes Portion of the cerebral cortex where vision registers in
the brain.
66
CHAPTER 2
HUM AN D IVERS I T Y
His and Hers Brains?
Are men’s and women’s brains specialized in different ways? Yes, to some extent.
Many physical differences between male and
female brains have been found, although
their significance remains debatable. In one
series of studies, researchers observed brain
activity while people did language tasks. Both
men and women showed increased activity
in Broca’s area, on the left side of the brain,
exactly as expected. Surprisingly, however,
the left and the right brain were activated in
more than half the women tested (Shaywitz
& Gore, 1995) ( Figure 2.24).
Using both sides of the brain for language may be a big advantage. When
Broca’s area is damaged, some women can
use the right side of their brains to compensate for the loss (Hochstenbach et al., 1998).
Thus, when a man says, “I have half a mind
to tell you what I think,” he may be stating
a curious truth. Despite this difference, the
two sexes performed equally well on a task
that involved sounding out words (Shaywitz
et al., 1995). The researchers concluded that
nature has given the brain different routes to
the same ability.
In a study of men and women with similar
IQ scores, brain images revealed major differ-
ences in brain areas involved in intelligence
(Haier et al., 2004). In general, the men had
more gray matter (neuron cell bodies), while
the women had more white matter (axons
coated in myelin). Further, the women had
more gray and white matter concentrated
in their frontal lobes than the men did. The
men’s gray matter was split between their
frontal and parietal lobes, while their white
matter was mostly in the temporal lobes.
Whatever else these differences mean, they
show that the human brain can be specialized in different ways to arrive at the same
capabilities.
Shaywitz et al., 1995 NMR Research/Yale Medical School
•
2.24
•sideFigure
in men.
Language tasks activate both sides of the brain in many women but only the left
primary visual area, the part of cortex to first receive input from
the eyes, experience blind spots in their vision.
Do the primary visual areas of the cortex correspond directly to
what is seen? Images are mapped onto the cortex, but the map is
greatly stretched and distorted (Carlson, 2007). That’s why it’s
important to avoid thinking of the visual area as being like a little
TV screen in the brain. Visual information creates complex patterns of activity in nerve cells; it does not make a TV-like image.
One of the most fascinating results of brain injury is visual
agnosia (ag-KNOW-zyah), an inability to identify seen objects.
Visual agnosia is often caused by damage to the association areas
on the occipital lobes (Farah, 2004). This condition is sometimes
referred to as “mindblindness.” For example, if we show Alice, an
agnosia patient, a candle, she can see it and can describe it as “a
long narrow object that tapers at the top.” Alice can even draw
the candle accurately, but she cannot name it. However, if she is
allowed to feel the candle, she will name it immediately. In short,
Alice can still see color, size, and shape. She just can’t form the
associations necessary to perceive the meanings of objects.
Are agnosias limited to objects? No. A fascinating form of “mindblindness” is facial agnosia, an inability to perceive familiar faces
(Farah, 2006). One patient with facial agnosia couldn’t recognize
her husband or mother when they visited her in the hospital, and
she was unable to identify pictures of her children. However,
as soon as a visitor spoke she knew them immediately by their
voices.
Areas devoted to recognizing faces lie in association areas on
the underside of the occipital lobes. These areas appear to have no
other function. Why would part of the brain be set aside solely for
identifying faces? From an evolutionary standpoint it is not really
so surprising. After all, we are social animals, for whom facial recognition is very important. This specialization is just one example
of what a marvelous organ of consciousness we possess.
How much do individual brains differ? Could we find different specializations from brain to brain? Perhaps. “His and Hers
Brains?” explains why.
In summary, the bulk of our daily experience and all of our
understanding of the world can be traced to the different areas
Brain and Behavior
of the cortex. The human brain is among the most advanced and
sophisticated of the brain-bearing species on earth. This, of course,
is no guarantee that this marvelous “biocomputer” will be put to
full use. Still, we must stand in awe of the potential it represents.
K N O W L E D GE B U I L D E R
Hemispheres and Lobes
of the Cerebral Cortex
RECITE
See if you can match the following:
1. _____ Corpus callosum
2. _____ Occipital lobes
3. _____ Parietal lobes
4. _____ Temporal lobes
5. _____ Frontal lobes
6. _____ Association cortex
7. _____ Aphasias
8. _____ Corticalization
9. _____ Left hemisphere
10. _____ Right hemisphere
11. _____ “Split brain”
12. _____ Agnosia
67
brain) can be fatal. Hunger, thirst, sleep, attention, sex, breathing,
and many other vital functions are controlled by parts of the subcortex. Let’s take a quick tour of these brain areas, which can be
divided into the brainstem (or hindbrain), the midbrain, and the
forebrain. (The forebrain also includes the cerebral cortex, which
we have already discussed because of its size and importance.) For
our purposes the midbrain can be viewed as a link between the
forebrain and the brainstem. Therefore, let us focus on the rest of
the subcortex ( Figure 2.25).
•
The Hindbrain
A.
B.
C.
D.
Visual area
Language, speech, writing
Motor cortex and abstract thinking
Spatial skills, visualization, pattern
recognition
E. Speech disturbances
F. Causes sleep
G. Increased ratio of cortex in brain
H. Bodily sensations
I. Treatment for severe epilepsy
J. Inability to identify seen objects
K. Fibers connecting the cerebral
hemispheres
L. Cortex that is not sensory or motor
in function
M. Hearing
REFLECT
Critical Thinking
13. If you wanted to increase the surface area of the cerebral cortex so
that more cerebral cortex would fit within the skull, how would you
do it?
14. If your brain were removed, replaced by another, and moved to a
new body, which would you consider to be yourself, your old body
with the new brain, or your new body with the old brain?
Relate
Learning the functions of the brain lobes is like learning areas on a map.
Try drawing a map of the cortex. Can you label all the different “countries”
(lobes)? Can you name their functions? Where is the primary motor area?
The somatosensory area? Broca’s area? Keep redrawing the map until it
becomes more detailed and you can do it easily.
Why are the lower brain areas so important? As the spinal cord joins
the brain, it widens into the brainstem. The brainstem consists
mainly of the medulla (meh-DUL-ah) and the cerebellum (ser-ahBEL-uhm). The medulla contains centers important for the reflex
control of vital life functions, including heart rate, breathing,
swallowing, and the like. Various drugs, diseases, and injuries can
disrupt the medulla and end or endanger life. That’s why a karate
chop to the back of the neck can be extremely dangerous.
The pons, which looks like a small bump on the brainstem, acts
as a bridge between the medulla and other brain areas. In addition
to connecting with many other locations, including the cerebellum, the pons influences sleep and arousal.
The cerebellum, which looks like a miniature cerebral cortex,
lies at the base of the brain. The cerebellum primarily regulates
posture, muscle tone, and muscular coordination. The cerebellum also stores memories related to skills and habits (Christian
& Thompson, 2005). Again we see that experience shapes the
brain: Musicians, who practice special motor skills throughout
their lives, have larger than average cerebellums (Hutchinson et
al., 2003).
bridges
In general, the cerebellum stores “know how” or “skill” memories.
“Know what” memories, such as remembering a person’s name or
knowing what the cerebellum does, are stored elsewhere in the
brain. See Chapter 8, page 260.
Primary visual area The part of occipital lobe that first receives input
from the eyes.
Answers: 1. K 2. A 3. H 4. M 5. C 6. L 7. E 8. G 9. B 10. D 11. I 12. J 13.
One solution would be to gather the surface of the cortex into folds, just
as you might if you were trying to fit a large piece of cloth into a small
box. This, in fact, is probably why the cortex is more convoluted (folded
or wrinkled) in higher animals. 14. Although there is no “correct” answer
to this question, your personality, knowledge, personal memories, and
self-concept all derive from brain activity — which makes a strong case
for your old brain in a new body being more nearly the “real you.”
Visual agnosia Inability to identify seen objects.
Facial agnosia Inability to perceive familiar faces.
The Subcortex — At the Core
of the (Brain) Matter
Gateway Question: What are the major parts of the subcortex?
You could lose large portions of your cerebral cortex and still survive. Not so with the subcortex, the brain structures immediately
below the cerebral cortex. Serious damage to the subcortex (lower
Subcortex All brain structures below the cerebral cortex.
Brainstem The lowest portions of the brain, including the cerebellum,
medulla, pons, and reticular formation.
Medulla The structure that connects the brain with the spinal cord and
controls vital life functions.
Pons An area on the brainstem that acts as a bridge between the
medulla and other structures.
Cerebellum A brain structure that controls posture and coordination.
68
CHAPTER 2
Cerebrum
(Surface: cerebral cortex)
Voluntary movements;
sensations, learning,
remembering, thinking,
emotion, consciousness
Corpus Callosum
Band of fibers connecting
the two hemispheres
Thalamus
Relay station to cortex for
sensory information
Hypothalamus
Control of hunger, thirst,
temperature, and other
visceral and bodily
functions
Midbrain
Conduction and
switching center
Cerebellum
Muscle tone; body balance;
coordination of skilled
movement
Pituitary Gland
The ”master gland”
of the endocrine system
Medulla
Centers for control over
breathing, swallowing,
digestion, heart rate
Reticular Formation
Arousal; attention;
movement; reflexes
Spinal Cord
Conduction paths for motor
and sensory impulses; local
reflexes (reflex arc)
Forebrain
Midbrain
Hindbrain
•
Figure 2.25 This simplified drawing shows the main structures of the human brain and describes some of their most important features. (You can use the color code in the foreground to identify which areas are part of the forebrain, midbrain, and hindbrain.)
What happens if the cerebellum is injured? Without the cerebellum, tasks like walking, running, or playing catch become impossible. The first symptoms of a crippling disease called spinocerebellar degeneration are tremor, dizziness, and muscular weakness.
Eventually, victims have difficulty merely standing, walking, or
feeding themselves.
Reticular Formation
A network of fibers and cell bodies called the reticular (rehTICK-you-ler) formation (RF) lies inside the medulla and brainstem. As messages flow into the brain, the RF gives priority to
some while turning others aside (Kalat, 2007). By doing so, the
RF influences attention. The RF doesn’t fully mature until adolescence, which may be why children have such short attention
spans. The RF also modifies outgoing commands to the body. In
this way the RF affects muscle tone, posture, and movements of
the eyes, face, head, body, and limbs. At the same time, the RF
controls reflexes involved in breathing, sneezing, coughing, and
vomiting.
The RF also keeps us vigilant, alert, and awake. Incoming messages from the sense organs branch into a part of the RF called
the reticular activating system (RAS). The RAS bombards the
cortex with stimulation, keeping it active and alert. For instance,
let’s say a sleepy driver rounds a bend and sees a deer standing in
the road. The driver snaps to attention and applies the brakes. She
can thank her RAS for arousing the rest of her brain and averting
an accident. If you’re getting sleepy while reading this chapter, try
pinching your ear — a little pain will cause the RAS to momentarily arouse your cortex.
The Forebrain
Like buried treasure, two of the most important parts of your body
lie deep within your brain. The thalamus (THAL-uh-mus) and
an area just below it called the hypothalamus (HI-po-THAL-uhmus) are key parts of the forebrain. (See Figure 2.25.)
How could these be any more important than other areas
already described? The thalamus acts as a final “switching station” for sensory messages on their way to the cortex. Vision,
hearing, taste, and touch all pass through this small, footballshaped structure. Thus, injury to even small areas of the thalamus can cause deafness, blindness, or loss of any other sense,
except smell.
The human hypothalamus is about the size of a small grape.
Small as it may be, the hypothalamus is a kind of master control
center for emotion and many basic motives (Carlson, 2007). The
hypothalamus affects behaviors as diverse as sex, rage, body temperature, hormone release, eating and drinking, sleep, waking, and
emotion. (See Chapter 10, pages 324–325.)
The hypothalamus is basically a “crossroads” that connects
many areas of the brain. It is also the final pathway for many kinds
of behavior. That is, the hypothalamus is the last place where many
behaviors are organized or “decided on” before messages leave the
brain, causing the body to react.
•
Brain and Behavior
The Limbic System
As a group, the hypothalamus, parts of the thalamus, the amygdala, the hippocampus, and other structures make up the limbic
system ( Figure 2.26). The limbic system has a major role in
producing emotion and motivated behavior. Rage, fear, sexual
response, and intense arousal can be localized to various points in
the limbic system. Laughter, a delightful part of human social life,
also has its origins in the limbic system (Cardoso, 2000).
During evolution, the limbic system was the earliest layer of
the forebrain to develop. In lower animals, the limbic system helps
organize basic survival responses: feeding, fleeing, fighting, or
reproduction. In humans, a clear link to emotion remains. The
amygdala (ah-MIG-dah-luh), in particular, is strongly related
to fear. For example, during medical testing one woman reacted
with a sudden outburst of fear and anger when the amygdala was
stimulated, saying, “I feel like I want to get up from this chair!
Please don’t let me do it! I don’t want to be mean! I want to get
something and just tear it up!” (King, 1961).
The amygdala provides a primitive, “quick pathway” to the cortex. Like lower animals, we can be startled and, as such, are able to
react to dangerous stimuli before we fully know what is going on.
In situations where true danger exists, such as in military combat,
the amygdala’s rapid response may aid survival. However, disorders
of the brain’s fear system can be very disruptive. An example is the
war veteran who involuntarily dives into the bushes when he hears
a car backfire (Fellous & LeDoux, 2005; LaBar & LeDoux, 2002).
The role of the amygdala in emotion may also explain why people
who suffer from phobias and disabling anxiety often feel afraid
without knowing why (LeDoux, 1999).
•
Cingulate gyrus
Mammillary body
Thalamus
Fornix
69
bridges
Unconscious fear produced by the amygdala seems to explain
why people who survive horrible experiences, such as a plane
crash, can have debilitating fears years later. See the discussion
of stress disorders in Chapter 14, page 483.
Some parts of the limbic system have taken on additional,
higher-level functions. A part called the hippocampus (HIP-ohCAMP-us) is important for forming lasting memories (Kumaran
& Maguire, 2005). The hippocampus lies inside the temporal
lobes, which is why stimulating the temporal lobes can produce
memory-like or dream-like experiences. The hippocampus also
helps us navigate through space. The right side of your hippocampus will become more active, for instance, if you mentally plan a
drive across town (Maguire, Frackowiak, & Frith, 1997).
Psychologists have discovered that animals will learn to press
a lever to deliver a dose of electrical stimulation to the limbic
system. The animals act like the stimulation is satisfying or pleasurable. Indeed, several areas of the limbic system act as reward,
or “pleasure,” pathways. Many are found in the hypothalamus,
where they overlap with areas that control thirst, sex, and hunger. Commonly abused drugs, such as cocaine, amphetamine,
heroin, nicotine, marijuana, and alcohol, activate many of the
same pleasure pathways. This appears to be part of the reason
why these drugs are so powerfully rewarding (Kandel, Schwartz,
& Jessell, 2003). You might also be interested to know that
music you would describe as “thrilling” activates pleasure systems in your brain. This may explain some of the appeal of
music that can send shivers down your spine (Blood & Zatorre,
2001). (It may also explain why people will pay so much for
concert tickets!)
Punishment, or “aversive,” areas have also been found in the
limbic system. When these locations are activated, animals show
discomfort and will work hard to turn off the stimulation. Because
much of our behavior is based on seeking pleasure and avoiding
pain, these discoveries continue to fascinate psychologists.
Reticular formation (RF) A network within the medulla and brainstem;
associated with attention, alertness, and some reflexes.
Reticular activating system (RAS) A part of the reticular formation
that activates the cerebral cortex.
Hippocampus
Hypothalamus
Thalamus A brain structure that relays sensory information to the
cerebral cortex.
Hypothalamus A small area of the brain that regulates emotional
behaviors and motives.
Amygdala
2.26 Parts of the limbic system. Although only one side is shown
•here,Figure
the hippocampus and the amygdala extend out into the temporal lobes at
each side of the brain. The limbic system is a sort of “primitive core” of the brain
strongly associated with emotion.
Limbic system A system in the forebrain that is closely linked with
emotional response.
Amygdala A part of the limbic system associated with fear responses.
Hippocampus A part of the limbic system associated with storing
memories.
70
CHAPTER 2
The Magnificent Brain
Given the amount of information covered in our journey through
the brain, a short review is in order. We have seen that the human
brain is an impressive assembly of billions of sensitive cells and
nerve fibers. The brain controls vital bodily functions, keeps track
of the external world, issues commands to the muscles and glands,
responds to current needs, regulates its own behavior, and even
creates the “mind” and the magic of consciousness — all at the
same time.
A final note of caution is now in order. For the sake of simplicity we have assigned functions to each “part” of the brain as if it
were a computer. This is only a half-truth. In reality, the brain is
a vast information-processing system. Incoming information scatters all over the brain and converges again as it goes out through
the spinal cord, to muscles and glands. The overall system is much,
much more complicated than our discussion of separate “parts”
implies. In addition, the brain constantly revises its circuits in
response to changing life experiences (Kolb & Whishaw, 2006).
We began our exploration of the brain with a virtuoso performance. Imagine the other extreme of being completely unable to
move or speak. Even though you would remain alert and intelligent, you would be unable to communicate your simplest thoughts
and feelings to others. Each year, this is the fate of thousands of
people, like Kate Adamson, who are paralyzed by stroke, disease,
or injury. In a very real sense, these people are locked in, prisoners
in their own bodies (Smith & Delargy, 2005).
What if they could “will” a computer to speak for them? Right
on! Researchers have developed brain–computer interfaces that
translate a patient’s EEG recordings into commands that can
be used to control a computer (Hinterberger et al., 2003)
and even access the Internet (Karim et al., 2006).
in many ways (Carlson, 2007). Here is a brief sample: Pregnancy
and motherhood cause the release of hormones that lead to the
dramatic changes involved in maternal behavior (Kingsley & Lambert, 2006). Hormone output from the adrenal glands rises during
stressful situations; androgens (“male” hormones) are related to
the sex drive in both males and females; hormones secreted during times of high emotion intensify memory formation; at least
some of the emotional turmoil of adolescence is due to elevated
hormone levels; different hormones prevail when you are angry,
rather than fearful. Even disturbing personality patterns may be
linked to hormonal irregularities (Evardone, Alexander, & Morey,
2007).
In fact, something as routine as watching a movie can alter
hormone levels. After watching violent scenes from The Godfather, men had higher levels of the male hormone testosterone.
For both men and women, watching a romantic film boosted
a hormone that’s linked to relaxation and reproduction (Schultheiss, Wirth, & Stanton, 2004). Because these are just samples,
let’s consider some additional effects hormones have on the body
and behavior.
The pituitary is a pea-sized globe hanging from the base of
the brain. (Return to Figure 2.27.) One of the pituitary’s more
important roles is to regulate growth. During childhood, the
pituitary secretes a hormone that speeds body development. If too
little growth hormone is released, a person may remain far smaller
than average. If this condition is not treated, a child may be 6 to
12 inches shorter than age-mates. As adults, some will have hypoPineal gland
(helps regulate
body rhythms
and sleep cycles)
Pituitary gland
(influences growth and
lactation; also regulates
the activity of other glands)
The Endocrine System —
My Hormones Made Me Do It
Gateway Question: Does the glandular system affect
behavior?
Our behavior is not solely a product of the nervous
system. The endocrine (EN-duh-krin) glands form an
equally important parallel communication system in
the body. The endocrine system is made up of glands
that secrete chemicals directly into the bloodstream or
lymph system ( Figure 2.27). These chemicals, called
hormones, are carried throughout the body, where
they affect both internal activities and visible behavior. Hormones are related to neurotransmitters. Like
other transmitter chemicals, hormones activate cells
in the body. To respond, the cells must have receptor
sites for the hormone. Hormones affect puberty, personality, dwarfism, jet lag, and much more.
How do hormones affect behavior? Although we are
seldom directly aware of them, hormones affect us
•
Thyroid gland
(regulates the rate of
metabolism in the body)
Adrenal glands
(secretes hormones
that arouse the body,
help with adjustment
to stress, regulate salt
balance, and affect
sexual functioning)
•
Pancreas
(releases insulin to regulate
blood sugar and hunger)
Testes
(secrete testosterone,
which influences male
sexual function)
• Figure 2.27
Ovaries
(secrete estrogen, which
influences female sexual
function)
Brain and Behavior
pituitary (HI-po-pih-TU-ih-ter-ee) dwarfism. Such individuals are
perfectly proportioned, but tiny. Regular injections of growth
hormone can raise a hypopituitary child’s height by several inches,
usually to the short side of average.
Too much growth hormone produces gigantism (excessive
bodily growth). Secretion of too much growth hormone late in
the growth period causes acromegaly (AK-row-MEG-uh-lee), a
condition in which the arms, hands, feet, and facial bones become
enlarged. Acromegaly produces prominent facial features, which
some people have used as a basis for careers as character actors,
wrestlers, and the like.
The pituitary also governs the functioning of other glands
(especially the thyroid, adrenal glands, and ovaries or testes).
These glands in turn regulate such bodily processes as metabolism,
responses to stress, and reproduction. In women, the pituitary
controls milk output during breast-feeding.
The pituitary is often called the “master gland” because it
influences other endocrine glands. But the master has a master:
The pituitary is directed by the hypothalamus, which lies directly
above it. In this way, the hypothalamus can affect glands throughout the body. This, then, is the major link between the brain and
hormones (Carlson, 2007).
The pineal (pin-EE-ul) gland was once considered a useless
remnant of evolution. In certain fishes, frogs, and lizards, the
gland is associated with a well-developed light-sensitive organ, or
so-called third eye. In humans, the function of the pineal gland is
just now coming to light (so to speak). The pineal gland releases
a hormone called melatonin (mel-ah-TONE-in) in response to
71
daily variations in light. Melatonin levels in the bloodstream rise
at dusk and peak around midnight and fall again as morning
approaches. As far as the brain is concerned, it’s bedtime when
melatonin levels rise (Kennaway & Wright, 2002).
bridges
Melatonin can be used to reset the body’s “clock” and minimize
jet lag for long-distance pilots, aircrews, and travelers. See
Chapter 10, pages 322–323.
The thyroid gland, located in the neck, regulates metabolism.
As you may remember from a biology course, metabolism is the
rate at which energy is produced and expended in the body. By
altering metabolism, the thyroid can have a sizable effect on
personality. A person suffering from hyperthyroidism (an overactive thyroid) tends to be thin, tense, excitable, and nervous. An
underactive thyroid (hypothyroidism) in an adult can cause inactivity, sleepiness, slowness, obesity, and depression ( Joffe, 2006).
In infancy, hypothyroidism limits development of the nervous
system, leading to severe mental retardation. (See Chapter 9,
pages 309–310.)
When you are frightened or angry, some important reactions
prepare your body for action: Your heart rate and blood pressure rise, stored sugar is released into the bloodstream for quick
energy, your muscles tense and receive more blood, and your
blood is prepared to clot more quickly in case of injury. As we
Endocrine system Glands whose secretions
pass directly into the bloodstream or lymph
system.
Getty Images
Amanda Edwards/Getty Images
Hormone A glandular secretion that affects
bodily functions or behavior.
Underactivity of the pituitary gland may produce a dwarf. Verne Troyer, best known for playing Mini-Me in
the Austin Powers movies, has enjoyed an impressive career as an actor. Overactivity of the pituitary gland
may produce a giant. Until his premature death in 2005, actor Matthew McGrory was best known for his role
of Karl the Giant in the 2003 movie Big Fish.
Growth hormone A hormone, secreted
by the pituitary gland, that promotes body
growth.
Pituitary gland The “master gland” whose
hormones influence other endocrine glands.
Pineal gland Gland in the brain that helps
regulate body rhythms and sleep cycles.
Melatonin Hormone released by the pineal
gland in response to daily cycles of light and
dark.
Thyroid gland Endocrine gland that helps
regulate the rate of metabolism.
CHAPTER 2
discussed earlier, these changes are controlled by the autonomic
nervous system. Specifically, the sympathetic branch of the ANS
causes the hormones epinephrine (ep-eh-NEF-rin) and norepinephrine to be released by the adrenal glands. (Epinephrine is
also known as adrenaline, which may be more familiar to you.)
Epinephrine, which is associated with fear, tends to arouse the
body. Norepinephrine also tends to arouse the body, but it is
linked with anger.
The adrenal glands are located just under the back of the rib
cage, atop the kidneys. The adrenal medulla, or inner core of the
adrenal glands, is the source of epinephrine and norepinephrine.
The adrenal cortex, or outer “bark” of the adrenal glands, produces
a set of hormones called corticoids (KOR-tih-coids). One of their
jobs is to regulate salt balance in the body. A deficiency of certain
corticoids can evoke a powerful craving for the taste of salt in
humans. The corticoids also help the body adjust to stress, and
they are a secondary source of sex hormones.
An oversecretion of the adrenal sex hormones can cause virilism (exaggerated male characteristics). For instance, a woman may
grow a beard or a man’s voice may become so low it is difficult
to understand. Oversecretion early in life can cause premature
puberty (full sexual development during childhood). One of the
most remarkable cases on record is that of a 5-year-old Peruvian
girl who gave birth to a son (Strange, 1965).
While we are on the topic of sex hormones, there is a related
issue worth mentioning. One of the principal androgens, or
“male” hormones, is testosterone, which is supplied in small
amounts by the adrenal glands. (The testes are the main source of
testosterone in males.) Perhaps you have heard about the use of
anabolic steroids by athletes who want to “bulk up” or promote
muscle growth. Most of these drugs are synthetic versions of
testosterone.
Although there is some disagreement about whether steroids
actually improve athletic performance, it is widely accepted that
they may cause serious side effects. Problems include voice deepening or baldness in women and shrinkage of the testicles, sexual
impotence, or breast enlargement in men (Millman & Ross, 2003).
Dangerous increases in hostility and aggression (“roid rage”) have
also been linked with steroid use (Hartgens & Kuipers, 2004).
Also common when steroids are used by younger adolescents
are an increased risk of heart attack and stroke, liver damage, or
stunted growth. Understandably, almost all major sports organizations ban the use of anabolic steroids.
In this brief discussion of the endocrine system we have considered only a few of the more important glands. Nevertheless,
this should give you an appreciation of how completely behavior and personality are tied to the ebb and flow of hormones in
the body.
A Look Ahead
In the upcoming “Psychology in Action” section, we will return
to the brain to see how hand preference relates to brain organization. You’ll also find out if being right- or left-handed affects your
chances of living to a ripe old age.
KNOWL E DG E B U I L DE R
Subcortex and Endocrine System
RECITE
1. Three major divisions of the brain are the brainstem or
_____________________, the _____________________,
and the ___________________.
2. Reflex centers for heartbeat and respiration are found in the
a. cerebellum
b. thalamus
c. medulla
d. RF
3. A portion of the reticular formation, known as the RAS, serves
as an ______________ system in the brain.
a. activating
b. adrenal
c. adjustment
d. aversive
4. The _____________ is a final relay, or “switching station,” for
sensory information on its way to the cortex.
5. “Reward” and “punishment” areas are found throughout the
_____________ system, which is also related to emotion.
6. Undersecretion from the thyroid can cause both
a. dwarfism
b. gigantism
c. obesity
d. mental retardation
7. The body’s ability to resist stress is related to the action of the
adrenal _________________.
REFLECT
Critical Thinking
8. Subcortical structures in humans are quite similar to corresponding
lower brain areas in animals. Why would knowing this allow you
to predict, in general terms, what functions are controlled by the
subcortex?
9. Where in all the brain’s “hardware” do you think the mind is found?
What is the relationship between mind and brain?
Relate
If Mr. Medulla met Ms. Cerebellum at a party, what would they say their
roles are in the brain? Would a marching band in a “reticular formation”
look like a network? Would it get your attention? If you were standing in
the final path for behavior leaving the brain, would you be in the thalamus? Or in the hy-path-alamus (please forgive the misspelling)? When
you are emotional, do you wave your limbs around (and does your limbic
system become more active)?
Name as many of the endocrine glands as you can. Which did
you leave out? Can you summarize the functions of each of the
glands?
Answers: 1. hindbrain, midbrain, forebrain 2. c 3. a 4. thalamus
5. limbic 6. c, d (in infancy) 7. cortex 8. Because the subcortex must
be related to basic functions common to all higher animals: motives,
emotions, sleep, attention, and vegetative functions, such as heartbeat, breathing, and temperature regulation. The subcortex also routes
and processes incoming information from the senses and outgoing
commands to the muscles. 9. This question, known as the mind–body
problem, has challenged thinkers for centuries. One recent view is
that mental states are “emergent properties” of brain activity. That is,
brain activity forms complex patterns that are, in a sense, more than
the sum of their parts. Or, to use a rough analogy, if the brain were a
musical instrument, then mental life would be like music played on
that instrument.
72
Brain and Behavior
73
P S YC HOL O GY IN A CT ION
Handedness — Are You Dexterous or Sinister?
Gateway Question: In what ways do rightand left-handed individuals differ?
Around the world, left-handedness has been
frowned upon. “Lefties” have often been
characterized as clumsy, awkward, unlucky,
or insincere. The Latin word for left is actually sinister! In contrast, right-handedness is
the paragon of virtue. The Latin word for
right is dexter, and “righties” are more likely
to be referred to as dexterous, coordinated,
skillful, and just. But is there any basis in fact
for these attitudes?
What causes handedness (a preference
for the right or left hand)? Why are there
more right-handed than left-handed people?
How do left-handed and right-handed people differ? Does being left-handed create any
problems—or benefits? The answers to these
questions lead us back to the brain, where
handedness begins. Let’s see what research has
revealed about handedness, the brain, and you.
Assessing Handedness
Write your name on a sheet of paper, first using
your right hand and then your left. You were
probably much more comfortable writing with
your dominant hand. This is interesting because
there’s no real difference in the strength or dexterity of the hands themselves. The agility of
your dominant hand is an outward expression
of superior motor control on one side of the
brain. If you are right-handed, there is literally
more area on the left side of your brain devoted
to controlling your right hand. If you are lefthanded, the reverse applies.
The preceding exercise implies that you are
either entirely right- or left-handed. But handedness is a matter of degree. To better assess
your handedness, complete a few questions
adapted from the Waterloo Handedness Questionnaire (Brown et al., 2006) by checking an
answer for each question. The more “Rights”
you check, the more right-handed you are.
Are You Right- or Left-Handed?
1. Which hand would you use to spin a
top?
____Right ____Left ____Either
2. With which hand would you hold a
paintbrush to paint a wall?
____Right ____Left ____Either
3. Which hand would you use to pick up a
book?
____Right ____Left ____Either
4. With which hand would you use a
spoon to eat soup?
____Right ____Left ____Either
5. Which hand would you use to flip
pancakes?
____Right ____Left ____Either
6. Which hand would you use to pick up
a piece of paper?
____Right ____Left ____Either
7. Which hand would you use to draw a
picture?
____Right ____Left ____Either
8. Which hand would you use to insert
and turn a key in a lock?
____Right ____Left ____Either
9. Which hand would you use to insert a
plug into an electrical outlet?
____Right ____Left ____Either
10. Which hand would you use to throw a
ball?
____Right ____Left ____Either
About 90 percent of all humans are righthanded; 10 percent are left-handed. Most
people (about 75 percent) are strongly rightor left-handed. The rest show some inconsistency in hand preference. Which were you?
Is there such a thing as being left-footed?
Excellent question. Do you have “two left feet”?
Sidedness is often measured by assessing hand,
foot, eye, and ear preference (Greenwood et
al., 2006). We also generally prefer breathing
through one nostril over the other and even
have a preference for which direction we lean
our head when kissing (Barrett, Greenwood,
& McCullagh, 2006). (Do you kiss “right”?)
Nevertheless, handedness remains the single most
important behavioral indicator of sidedness.
If a person is strongly left-handed, does that
mean the right hemisphere is dominant? Not
necessarily. It’s true that the right hemisphere
controls the left hand, but a left-handed person’s
language-producing, dominant hemisphere
may be on the opposite side of the brain.
Brain Dominance
About 97 percent of right-handers process
speech in the left hemisphere and are leftbrain dominant ( Figure 2.28). A good 68
percent of left-handers produce speech from
the left hemisphere, just as right-handed people do. About 19 percent of all lefties and
3 percent of righties use their right brain for
language. Some left-handers (approximately
12 percent) use both sides of the brain for
language processing. All told, 94 percent of
the population uses the left brain for language
(Coren, 1992).
•
Is there any way for a person to tell which
of his or her hemispheres is dominant? One
classic clue is the way you write. Righthanded individuals who write with a straight
hand, and lefties who write with a hooked
hand, are usually left-brain dominant for language. Left-handed people who write with
their hand below the line, and righties who
use a hooked position, are usually right-brain
dominant (Levy & Reid, 1976). Another hint
is provided by hand gestures. If you gesture
mostly with your right hand as you talk,
you probably process language in your left
hemisphere. Gesturing with your left hand is
associated with right-brain language processing (Hellige, 1993).
Epinephrine An adrenal hormone that
tends to arouse the body; epinephrine
is associated with fear. (Also known as
adrenaline.)
Norepinephrine An adrenal hormone that
tends to arouse the body; norepinephrine
is associated with anger. (Also known as
noradrenaline.)
Adrenal glands Endocrine glands that
arouse the body, regulate salt balance,
adjust the body to stress, and affect sexual
functioning.
Handedness A preference for the right or
left hand in most activities.
Sidedness A combination of preference for
hand, foot, eye, and ear.
Dominant hemisphere A term usually
applied to the side of a person’s brain that
produces language.
74
CHAPTER 2
•
Figure 2.28 Language is
controlled by the left side of the
brain in the majority of rightand left-handers.
Entire Population
Left-handers
Right-handers
Left 97%
Left 94%
Left 68%
Right 19%
Right 5%
Bilateral 1%
Bilateral 12%
Right 3%
Are your friends right-brained or leftbrained ( Figure 2.29)? Before you leap
to any conclusions, be aware that writing
position and gestures are not foolproof. The
only sure way to check brain dominance is
to do medical tests that involve assessing one
cerebral hemisphere at a time (Kirveskari,
Salmelin, & Hari, 2006).
•
Causes of Handedness
•
Hooked Left
Straight Left
Straight Right
Hooked Right
• Figure 2.29 Research suggests that the hand position used in writing may indicate which brain hemisphere
is used for language. (Redrawn from an illustration by M. E. Challinor.)
Advantage Right
Are there any drawbacks to being left-handed?
A small minority of lefties owe their hand preference to birth traumas (such as prematurity, low
birth weight, and breech birth). These individuals have higher rates of allergies, learning disorders, and other problems (Betancur et al., 1990).
Similarly, people with inconsistent handedness
(as opposed to consistent left-handers) may be at
risk for more immune-related diseases (Bryden,
Bruyn, & Fletcher, 2005).
Is it true that right-handed people live longer than left-handed people? It is true that there
is a shortage of very old lefties. One possible
explanation lies in the widespread finding that
left-handers are more accident-prone (Dutta &
Mandal, 2005). However, the supposed clumsiness of lefties may well be a result of living in
•
Figure 2.30 In this ultrasound image, a 4-month-old
fetus sucks her right thumb.
A study by psychologist Peter
Hepper suggests that she will
continue to prefer her right
hand after she is born and that
she will be right-handed as an
adult.
Custom Medical Stock Photo
Is handedness inherited from parents? Yes, at
least partly. Clear hand preferences are apparent even before birth, as can be seen in a fetal
ultrasound image ( Figure 2.30). According
to British psychologist Peter Hepper, prenatal handedness preferences persist for at least
10 years after birth (Hepper, McCartney, &
Shannon, 1998; Hepper, Wells, & Lynch,
2005). This suggests that handedness cannot
be dictated. Parents should never try to force a
left-handed child to use the right hand. To do
so may create speech or reading problems.
Studies of twins show that hand preferences are not directly inherited like eye color
or skin color (Ooki, 2005; Reiss et al., 1999).
Yet, two left-handed parents are more likely
to have a left-handed child than two righthanded parents are (McKeever, 2000). The
best evidence to date shows that handedness is
influenced by a single gene on the X (female)
chromosome ( Jones & Martin, 2001).
On the other hand, environmental factors
such as learning, birth traumas, and social pressure to use the right hand can also affect which
hand you end up favoring (Bailey & McKeever,
2004; McKeever et al., 2000). In the past, many
left-handed children were forced to use their
right hand for writing, eating, and other skills.
This is especially true in collectivist cultures
like India and Japan, where left-handedness is
viewed as especially negative. Not surprisingly,
the proportion of left-handers in these societies
is only about half that found in individualist
cultures such as the United States and Canada
(Ida & Mandal, 2003).
Advantage Left
Actually, there are some clear advantages to
being left-handed. Throughout history a notable number of artists have been lefties, from
Leonardo da Vinci and Michelangelo to Pablo
Picasso and M. C. Escher. Conceivably, because
the right hemisphere is superior at imagery and
visual abilities, there is some advantage to using
the left hand for drawing or painting (Springer
& Deutsch, 1998). At the least, lefties are definitely better at visualizing three-dimensional
objects. This may be why there are more lefthanded architects, artists, and chess players
than would be expected (Coren, 1992).
Similarly, being right-handed does not
guarantee sports superiority, as you can see
in Table 2.1.
By the way, chalk up a few more for the lefthanders, who have also done well in handball
(Dane & Erzurumluoglu, 2003) and professional tennis (Holtzen, 2000).
Lateralization refers to specialization in
the abilities of the brain hemispheres. One
striking feature of lefties is that they are gen-
•
Table 2.1
• Sports and Handedness
Sport
Handedness
Advantage
Baseball
No overall left or
right advantage
Boxing
Left
Fencing
Left
Basketball
Mixed and
ambidextrous
Ice hockey
Mixed and
ambidextrous
Field hockey
Mixed and
ambidextrous
Tennis
Strong left or strong
right
Squash
Strong left or strong
right
Badminton
Strong left or strong
right
Left-handers have an advantage in sports such as fencing and boxing. Most likely, their movements are less
familiar to opponents, who usually face right-handers
(Coren, 1992).
Adapted from Coren, 1992.
erally less lateralized than the right-handed.
In fact, even the physical size and shape of
their cerebral hemispheres are more alike. If
you are a lefty, you can take pride in the fact
that your brain is less lopsided than most! In
general, left-handers are more symmetrical on
almost everything, including eye dominance,
fingerprints — even foot size (Polemikos &
Papaeliou, 2000).
In some situations, less lateralization may
be a real advantage. For instance, individuals
who are moderately left-handed or ambidextrous seem to have better than average pitch
memory, which is a basic musical skill. Correspondingly, more musicians are ambidextrous
than would normally be expected (Springer &
Deutsch, 1998).
K N O WL E D GE B U I L D E R
Handedness and Brain Lateralization
RECITE
1. About 97 percent of left-handed people process language on the
left side of the brain, the same as right-handed people do. T or F?
2. Left-handed individuals who write with their hand below the writing
line are likely to be right-brain dominant. T or F?
3. People basically learn to be right- or left-handed. T or F?
4. In general, left-handed individuals show less lateralization in the
brain and throughout the body. T or F?
REFLECT
Critical Thinking
5. News reports that left-handed people tend to die younger have been
flawed in an important way: The average age of people in the lefthanded group was younger than that of subjects in the right-handed
group. Why would this make a difference in the conclusions drawn?
Math abilities may also benefit from fuller
use of the right hemisphere. Students who are
extremely gifted in math are much more likely
to be left-handed or ambidextrous (Benbow,
1986). Even where ordinary arithmetic skills
are concerned, lefties seem to excel (Annett,
2002; Annett & Manning, 1990).
The clearest advantage of being lefthanded shows up when there is a brain injury.
Because of their milder lateralization, lefthanded individuals typically experience less
language loss after damage to either brain
hemisphere, and they recover more easily
(Geschwind, 1979). Maybe having “two left
feet” isn’t so bad after all.
Relate
Think for a moment about what you “knew” about handedness and lefthanded people before you read this section. Which of your beliefs were
correct? How has your knowledge about handedness changed?
Answers: 1. F 2. T 3. F 4. T 5. Because we can’t tell if handedness or
average age accounts for the difference in death rates. For example, if
we start with a group of 20- to 30-year-old people, in which some die,
the average age of death has to be between 20 and 30. If we start with
a group of 30- to 40-year-old people, in which some die, the average
age of death has to be between 30 and 40. Thus, the left-handed group
might have an earlier average age at death simply because members of
the group were younger to start with.
a right-handed world. One study showed that
left-handed locomotive engineers have higher
accident rates and suggested that the cause
was due to the design of locomotive controls
(Bhushan & Khan, 2006). If it can be gripped,
turned, or pulled, it’s probably designed for the
right hand. Even toilet handles are on the right
side. On the other hand, the shortage of very
old lefties may just reflect the fact that, in the
past, more left-handed children were forced to
become right-handed. That makes it look like
many lefties don’t survive to old age. In reality,
they do, but many of them are masquerading as
righties (Martin & Freitas, 2002)!
75
Bob Daemmrich/The Image Works
Brain and Behavior
Lateralization Differences between the two sides of the body,
especially differences in the abilities of the brain hemispheres.
76
CHAPTER 2
chapter in review
The dendrite and soma of a neuron combine neural input and send it
down the axon to the axon terminals for output across the synapse to
other neurons.
• The firing of an action potential (nerve impulse) is basically an
electrical event.
• Communication between neurons is chemical: Neurotransmitters cross the synapse, attach to receptor sites, and excite
or inhibit the receiving cell.
• Chemicals called neuropeptides regulate activity in the brain.
• All behavior can be traced to networks of neurons.
• The brain’s circuitry is not static. The brain can “rewire” itself
and even grow new nerve cells in response to changing environmental conditions.
The nervous system can be divided into the central nervous system
(CNS) and the peripheral nervous system (PNS), which includes the
somatic (bodily) and autonomic (involuntary) nervous systems.
• The brain carries out most of the “computing” in the nervous
system.
• The spinal cord connects the brain to the peripheral nervous
system and can process simple reflex arcs.
• The peripheral nervous system carries sensory information to
the brain and motor commands to the body.
• “Vegetative” and automatic bodily processes are controlled
by the autonomic nervous system, which has a sympathetic
branch and a parasympathetic branch.
A major brain research strategy involves the localization of function
to link specific structures in the brain with specific psychological or
behavioral functions.
• Biopsychologists study how processes in the body, brain, and
nervous system relate to behavior.
• To map the brain, researchers activate or disable specific areas
and observe changes in behavior.
• Brain structure is investigated though dissection and less intrusive CT scans and MRI scans.
• Brain function is investigated through clinical case studies, electrical stimulation, ablation, deep lesioning, electrical
recording, and microelectrode recording, as well as less intrusive EEG recordings, PET scans, and fMRI scans.
The human cerebral cortex is largely responsible for our ability to use
language, make tools, acquire complex skills, and live in complex social
groups. The cerebral cortex is divided into left and right hemispheres
connected by the corpus callosum. Each hemisphere is divided into four
lobes: the frontal lobes, the parietal lobes, the temporal lobes, and the
occipital lobes.
• The human brain is marked by advanced corticalization, or
enlargement of the cerebral cortex.
Gateways to Brain and Behavior
• The left cerebral hemisphere contains speech or language
“centers” in most people. It also specializes in writing, calculating, judging time and rhythm, and ordering complex
movements.
• The right hemisphere is largely nonverbal. It excels at spatial
and perceptual skills, visualization, and recognition of patterns, faces, and melodies.
• The left hemisphere is good at analysis and it processes
small details sequentially. The right hemisphere detects
overall patterns; it processes information simultaneously
and holistically.
• “Split brains” can be created by cutting the corpus callosum.
The split-brain individual shows a remarkable degree of independence between the right and left hemispheres.
• The most basic functions of the lobes of the cerebral cortex
are as follows: frontal lobes — motor control, speech, abstract
thought, and sense of self; parietal lobes — bodily sensation;
temporal lobes — hearing and language; occipital lobes —
vision. Damage to any of these areas will impair the named
functions.
• Primary sensory and motor areas are found on the lobes of the
cerebral cortex.
• Association areas on the cortex are neither sensory nor motor
in function. They are related to more complex skills such as
language, memory, recognition, and problem solving.
• Damage to either Broca’s area or Wernicke’s area causes speech
and language problems known as aphasias.
The brain can be subdivided into the forebrain, midbrain, and hindbrain. The subcortex includes hindbrain and midbrain brain structures
as well as the lower parts of the forebrain, below the cortex.
• The medulla contains centers essential for reflex control of
heart rate, breathing, and other “vegetative” functions.
• The cerebellum maintains coordination, posture, and muscle
tone.
• The reticular formation directs sensory and motor messages,
and part of it, known as the RAS, acts as an activating system
for the cerebral cortex.
• The thalamus carries sensory information to the cortex.
• The hypothalamus exerts powerful control over eating, drinking, sleep cycles, body temperature, and other basic motives
and behaviors.
• The limbic system is strongly related to emotion. It also
contains distinct reward and punishment areas and an area
known as the hippocampus that is important for forming
memories.
Brain and Behavior
Endocrine glands serve as a chemical communication system within
the body. The ebb and flow of hormones from the endocrine glands
entering the bloodstream affect behavior, moods, and personality.
• Many of the endocrine glands are influenced by the pituitary
(the “master gland”), which is in turn influenced by the hypothalamus. Thus, the brain controls the body through both the
fast nervous system and the slower endocrine system.
The vast majority of people are right-handed and therefore left-brain
dominant for motor skills. More than 90 percent of right-handed
persons and about 70 percent of the left-handed also produce speech
from the left hemisphere.
• Brain dominance and brain activity determine if you are righthanded, left-handed, or ambidextrous.
• Most people are strongly right-handed. A minority are
strongly left-handed. A few have moderate or mixed hand
preferences or they are ambidextrous. Thus, handedness is not
a simple either/or trait.
• Left-handed people tend to be less strongly lateralized than
right-handed people (their brain hemispheres are not as
specialized).
77
Probe the Brain Explore the motor homunculus of the brain
interactively.
Brain Maps Information on the functions of a healthy cortex and also
some effects of brain injury.
The Patient’s Journey: Living With Locked-In Syndrome Meet
Nick, who lives with locked-in syndrome after suffering brainstem
damage.
Endo 101: The Endocrine System A description of the endocrine
system and hormones.
Anabolic Steroid Abuse An article on steroids and steroid abuse
from the National Institute on Drug Abuse.
What Is “Handedness”? Information about handedness and brain
laterality, including a list of famous left handers.
The Sinister Hand Interview on handedness with Dr. Michael
Corballis.
Left Brain, Right Brain Article on popular conceptions of the differences between brain hemispheres.
Interactive Learning
Web Resources
For an up-to-date list of direct links to interesting sites, including
those listed here, visit the student companion site for this book at
www.cengage.com/psychology/coon
Introduction to Psychology: Gateways to Mind and Behavior Book
Companion Website
www.cengage.com/psychology/coon
Visit your book companion website, where you will find flash cards,
practice quizzes, “Web Links,” and more to help you study.
Neural Transmission View a series of animations about neural transmission illustrating the action potential and the resting potential.
Synaptic Transmission Read more detail about synaptic transmission or view an animation.
The Nervous System Explore an overview of the major divisions of
the nervous system.
The Whole Brain Atlas View images of various parts of the brain.
The PET Scan Read more about PET scans.
fMRI for Newbies Learn about fMRI; includes fMRI images.
Split Brain Consciousness Explore the cerebral hemispheres and
what happens when they are split.
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CHAPTER
3
Human Development
Gateway Theme
The principles of development help us better understand not only children, but our own
behavior as well.
Paul Kuroda/Superstock
Gateway Questions
• How do heredity and environment affect development?
• What can newborn babies do?
• Of what significance is a child’s emotional bond with adults?
• How important are parenting styles?
• How do children acquire language?
• How do children learn to think?
• Why is the transition from adolescence to adulthood
especially challenging?
78
•
•
How do we develop morals and values?
•
•
•
What is involved in well-being during later adulthood?
What are the typical tasks and dilemmas through the life
span?
How do people typically react to death?
How do effective parents discipline and communicate
with their children?
preview
It’s a Girl!
With those words, Olivia catches her first glimpse of Samantha, her
tiny newborn baby. Frankly, at the moment Samantha looks something like a prune, with pudgy arms, stubby legs, and lots of wrinkles. Yet she looks so perfect—at least in her parents’ eyes. As Olivia
and her husband Tom look at Samantha they wonder, “How will
her life unfold? What kind of a person will she be?”“Will Samantha
be a happy teenager?” “Will she marry, become a mother, find an
interesting career?” Tom and Olivia can only hope that by the time
Samantha is 83, she will have lived a full and satisfying life.
What if we could skip ahead through Samantha’s life and
observe her at various ages? What could we learn? Seeing the
world through her eyes would be fascinating and instructive. For
example, a child’s viewpoint can make us more aware of things
we take for granted. Younger children, in particular, are very literal
in their use of language. When Samantha was 3, she thought her
bath was too hot and said to Tom, “Make it warmer, daddy.” At first,
Tom was confused. The bath was already fairly hot. But then he
realized that what she really meant was, “Bring the water closer to
the temperature we call warm.” It makes perfect sense if you look
at it that way.
Research done by developmental psychologists tells a fascinating story about human growth and development. Let’s let
Olivia, Tom, and Samantha represent parents and children everywhere, as we see what psychology can tell us about the challenges of growing up, maturing, aging, and facing death. Tracing
Samantha’s development might even help you answer two very
important questions: How did I become the person I am today?
and Who will I become tomorrow?
Gateway Question: How do heredity and environment affect
development?
When we think of development we naturally think of children
“growing up” into adults. But even as adults we never really stop
changing. Developmental psychology, the study of progressive
changes in behavior and abilities, involves every stage of life from
conception to death (or “the womb to the tomb”). Heredity and
environment also affect us throughout life. Some events, such as
when Samantha achieves sexual maturity, are mostly governed by
heredity. Others, such as when Samantha learns to swim, read, or
drive a car, are primarily a matter of environment.
But which is more important, heredity or environment? Actually,
neither. Biopsychologist Donald Hebb once offered a useful analogy: To define the area of a rectangle, what is more important,
height or width? Of course, both dimensions are absolutely essential. If either is reduced to zero, there is no rectangle. Similarly, if
Samantha grows up to become a prominent civil rights lawyer, her
success will be due to both heredity and environment.
While heredity gives each of us a variety of potentials and limitations, these are, in turn, affected by environmental influences,
such as learning, nutrition, disease, and culture. Ultimately, the
person you are today reflects a continuous interaction, or interplay,
between the forces of nature and nurture (Kalat, 2007). Let’s look
in more detail at this dance.
Heredity
Heredity (“nature”) refers to the genetic transmission of physical
and psychological characteristics from parents to their children.
An incredible number of personal features are set at conception,
when a sperm and an ovum (egg) unite.
Myrleen Ferguson Cate/PhotoEdit
Nature and Nurture —
It Takes Two to Tango
Identical twins. Twins who share identical genes (identical twins) demonstrate the
powerful influence of heredity. Even when they are reared apart, identical twins
are strikingly alike in motor skills, physical development, and appearance. At the
same time, twins are less alike as adults than they were as children, which shows
environmental influences are at work (Larsson, Larsson, & Lichtenstein, 2004).
How does heredity operate? The nucleus of every human cell
contains DNA, deoxyribonucleic acid (dee-OX-see-RYE-bonew-KLEE-ik). DNA is a long, ladder-like chain of pairs of chemical molecules ( Figure 3.1). The order of these molecules, or
organic bases, acts as a code for genetic information. The DNA in
•
Developmental psychology The study of progressive changes in
behavior and abilities from conception to death.
Heredity (“nature”) The transmission of physical and psychological
characteristics from parents to offspring through genes.
DNA Deoxyribonucleic acid, a molecular structure that
contains coded genetic information.
79
80
CHAPTER 3
Figure 3.1 (Top left) Linked mol•ecules
(organic bases) make up the “rungs”
Sugar-phosphate
backbone
Organic
bases
Cell
Nucleus
Chromosome
Biophoto Associates/Science-Source/
Photo Researchers, Inc.
•
Figure 3.2 This image, made with a scanning electron microscope, shows
•several
pairs of human chromosomes. (Colors are artificial.)
is 1 chance in 4 that their children will get two blue-eye genes and
have blue eyes ( Figure 3.3).
In actuality, few of our characteristics are controlled by single
genes. Instead, most are polygenic (pol-ih-JEN-ik), or controlled
by many genes working in combination. Through the expression
of genes, heredity determines eye color, skin color, and susceptibility to some diseases. Also, genes can switch on (or off ) at certain
ages or developmental stages. In this way, heredity continues to
exert a powerful influence throughout maturation, the physical
growth and development of the body, brain, and nervous system.
As the human growth sequence unfolds, genetic instructions influence body size and shape, height, intelligence, athletic potential,
personality traits, sexual orientation, and a host of other details
(Cummings, 2006) ( Table 3.1).
•
•
Brown-eyed mother
Mother's
genes
Father's
genes
each cell contains a record of all the instructions needed to make a
human — with room left over to spare. In 2003, a major scientific
milestone was reached when the Human Genome Project completed sequencing all 3 billion chemical base pairs in human DNA
(U.S. Department of Energy Office of Science, 2005).
Human DNA is organized into 46 chromosomes. (The word
chromosome means “colored body.”) These thread-like structures
hold the coded instructions of heredity ( Figure 3.2). A notable
exception is sperm cells and ova, which contain only 23 chromosomes. Thus, Samantha received 23 chromosomes from Olivia
and 23 from Tom. This is her genetic heritage.
Genes are small areas of DNA that affect a particular process or
personal characteristic. Sometimes, a single gene is responsible for
an inherited feature, such as Samantha’s eye color. Genes may be
dominant or recessive. When a gene is dominant, the feature it
controls will appear every time the gene is present. When a gene is
recessive, it must be paired with a second recessive gene before its
effect will be expressed. For example, if Samantha got a blue-eye
gene from Tom and a brown-eye gene from Olivia, Samantha will
be brown-eyed, because brown-eye genes are dominant.
If brown-eye genes are dominant, why do two brown-eyed parents
sometimes have a blue-eyed child? If one or both parents have two
brown-eye genes, the couple’s children can only be brown-eyed.
But what if each parent has one brown-eye gene and one blue-eye
gene? In that case, both parents would have brown eyes. Yet there
Brown-eyed father
on DNA’s twisted “molecular ladder.” The
order of these molecules serves as a code
for genetic information. The code provides
a genetic blueprint that is unique for each
individual (except identical twins). The
drawing shows only a small section of a
DNA strand. An entire strand of DNA is
composed of billions of smaller molecules.
(Bottom left) The nucleus of each cell in
the body contains chromosomes made up
of tightly wound coils of DNA. (Don’t be
misled by the drawing: Chromosomes are
microscopic, and the chemical molecules
that make up DNA are even smaller.)
DNA
Brown-eyed child
Brown-eyed child
Blue-eyed child
Brown-eyed child
Figure 3.3 Gene patterns for children of brown-eyed parents, where each
•parent
has one brown-eye gene and one blue-eye gene. Because the brown-eye
gene is dominant, 1 child in 4 will be blue-eyed. Thus, there is a significant chance
that two brown-eyed parents will have a blue-eyed child.
Human Development
Table 3.1
81
• Human Growth Sequence
Period
Duration
Descriptive Name
Prenatal period
Germinal period
Embryonic period
Fetal period
From conception to birth
First 2 weeks after conception
2–8 weeks after conception
From 8 weeks after conception to birth
Zygote
Embryo
Fetus
Neonate
Neonatal period
Infancy
From birth to a few weeks after birth
From a few weeks after birth until child is walking securely; some children walk securely at less
than a year, while others may not be able to until age 17–18 months
Infant
Early childhood
From about 15–18 months until about 2–2½ years
From age 2–3 to about age 6
Toddler
Preschool child
Middle childhood
From about age 6 to age 12
School-age child
Pubescence
Period of about 2 years before puberty
Point of development at which biological changes of pubescence reach a climax marked by
sexual maturity
From the beginning of pubescence until full social maturity is reached (difficult to fix duration of
this period)
Adolescent
Adulthood
Young adulthood (19–25)
Adulthood (26–40)
Maturity (41 plus)
From adolescence to death; sometimes subdivided into other periods as shown at left
Adult
Senescence
No defined limit that would apply to all people; extremely variable; characterized by marked
physiological and psychological deterioration
Adult (senile), “old age”
Puberty
Adolescence
*Note: There is no exact beginning or ending point for various growth periods. The ages are approximate, and each period may be thought of as blending into the next.
Table courtesy of Tom Bond.
Readiness
At what ages will Samantha be ready to feed herself, to walk alone,
or to say goodbye to diapers? Such milestones tend to be governed
by a child’s readiness for rapid learning. That is, minimum levels
of maturation must occur before some skills can be learned. Parents are asking for failure when they try to force a child to learn
skills too early (Schum et al., 2002). It is impossible, for instance,
to teach children to walk or use a toilet before they have matured
enough to control their bodies.
Consider the eager parents who toilet trained an 18-month-old
child in 10 trying weeks of false alarms and “accidents.” If they had
waited until the child was 24 months old, they might have succeeded in just 3 weeks. Parents may control when toilet training
starts, but maturation tends to dictate when it will be completed
(Schum et al., 2002). The average age for completed toilet training
is about 3 years (girls a little earlier, boys a little later) (Schum et
al., 2001). So why fight nature? (The wet look is in.)
connections disappear. As a result, early learning environments literally shape the developing brain, through “blooming and pruning” of
synapses (Nelson, 1999).
Although human culture is accelerating the rate at which
human DNA is evolving, modern humans are still genetically
quite similar to cave dwellers who lived 30,000 years ago (Hawks
et al., 2007). Nevertheless, a bright baby born today could learn to
become almost anything — a ballet dancer, an engineer, a gangsta
rapper, or a biochemist who likes to paint in watercolors. But an
Chromosomes Thread-like “colored bodies” in the nucleus of each cell
that are made up of DNA.
Genes Specific areas on a strand of DNA that carry hereditary
information.
Dominant gene A gene whose influence will be expressed each time
the gene is present.
Recessive gene A gene whose influence will be expressed only when it
is paired with a second recessive gene.
Environment
Our environment also exerts a profound influence on our development. Environment (“nurture”) refers to the sum of all external
conditions that affect a person. For example, the brain of a newborn
baby has fewer dendrites (nerve cell branches) and synapses (connections between nerve cells) than an adult brain ( Figure 3.4). However, the newborn brain is highly plastic (capable of being altered
by experience). During the first 3 years of life, millions of new
connections form in the brain every day. At the same time, unused
•
Polygenic characteristics Personal traits or physical properties that
are influenced by many genes working in combination.
Maturation The physical growth and development of the body and
nervous system.
Readiness A condition that exists when maturation has advanced
enough to allow the rapid acquisition of a particular skill.
Environment (“nurture”) The sum of all external conditions affecting
development, including especially the effects of learning.
•
CHAPTER 3
Neonate
Six months
Two years
Figure 3.4
A rapid increase in brain synapses continues until about age 4. At
that point, children actually have more brain synapses than adults do. Then, after
age 10, the number slowly declines, reaching adult levels at about age 16. (Reprinted
by permission of the publisher from The Postnatal Development of the Human Cerebral Cortex,
Vols. I–III by Jesse LeRoy Conel, Cambridge, MA: Harvard University Press, Copyright © 1939, 1975
by the President and Fellows of Harvard College.)
Upper Paleolithic baby could have only become a hunter or food
gatherer.
Prenatal Influences
Petit Format/Photo Researchers, Inc.
Environmental factors actually start influencing development
before birth. Although the intrauterine environment (interior
of the womb) is highly protected, environmental conditions can
nevertheless affect the developing child. For example, when Olivia
was pregnant, Samantha’s fetal heart rate and movements increased
when loud sounds or vibrations penetrated the womb (Kisilevsky
et al., 2004).
If Olivia’s health or nutrition had been poor, or if she had German measles, syphilis, or HIV; or used drugs; or was exposed to
X-rays or radiation, Samantha’s growth sequence might have been
harmed. In such cases babies can suffer from congenital problems, or “birth defects.” These environmental problems affect the
Because of the rapid growth of basic structures, the developing fetus is sensitive
to a variety of diseases, drugs, and sources of radiation. This is especially true
during the first trimester (3 months) of gestation (pregnancy).
developing fetus and become apparent at birth. In contrast, genetic
disorders are inherited from parents. Examples are sickle-cell anemia, hemophilia, cystic fibrosis, muscular dystrophy, albinism,
and some types of mental retardation.
How is it possible for the embryo or the fetus to be harmed? No
direct intermixing of blood takes place between a mother and her
unborn child. Yet some substances — especially drugs — do reach
the fetus. Anything capable of directly causing birth defects is
called a teratogen (teh-RAT-uh-jen). Sometimes women are
exposed to powerful teratogens, such as radiation, lead, pesticides,
or polychlorinated biphenyls (PCBs), without knowing it. But
pregnant women do have direct control over many teratogens. For
example, a woman who takes cocaine runs a serious risk of injuring
her fetus (Schuetze & Eiden, 2006). In short, when a pregnant
woman takes drugs, her unborn child does too.
Unfortunately, in the United States this is one of the greatest
risk factors facing unborn children (Coles & Black, 2006). If a
mother is addicted to morphine, heroin, or methadone, her baby
may be born with an addiction. Repeated heavy drinking during
pregnancy causes fetal alcohol syndrome (FAS). Affected infants
have low birth weight, a small head, bodily defects, and facial malformations. Many also suffer from emotional, behavioral, and
mental handicaps (Golden, 2005).
Tobacco is also harmful. Smoking during pregnancy greatly
reduces oxygen to the fetus. Heavy smokers risk miscarrying or
having premature, underweight babies who are more likely to die
soon after birth. Children of smoking mothers score lower on tests
of language and mental ability (Huijbregts et al., 2006). In other
words, an unborn child’s future can go “up in smoke.” That goes
for marijuana as well (Viveros et al., 2005).
Ted Wood
82
Some of the typical features of children suffering from fetal alcohol syndrome
(FAS) include a small nonsymmetrical head, a short nose, a flattened area
between the eyes, oddly shaped eyes, and a thin upper lip. Many of these features become less noticeable by adolescence. However, mental retardation and
other problems commonly follow the FAS child into adulthood. The child shown
here represents a moderate example of FAS.
Human Development
83
Early experiences can have particularly lasting effects. For example,
children who are abused may suffer lifelong emotional problems
(Goodwin, Fergusson, & Horwood, 2005). At the same time, extra
care can sometimes reverse the effects of a poor start in life (Bornstein & Tamis-LeMonda, 2001). In short, environmental forces
guide human development, for better or worse, throughout life.
Why do some experiences have more lasting effects than others?
Part of the answer lies in sensitive periods. These are times when
children are more susceptible to particular types of environmental
influences. Events that occur during a sensitive period can permanently alter the course of development (Bruer, 2001). For example,
forming a loving bond with a caregiver early in life seems to be
crucial for optimal development. Likewise, babies who don’t hear
normal speech during their first year may have impaired language
abilities (Thompson & Nelson, 2001).
Allen Russell/Photolibrary
Sensitive Periods
Children who grow up in poverty run a high risk of experiencing many forms of
deprivation. There is evidence that lasting damage to social, emotional, and cognitive development occurs when children must cope with severe early deprivation.
Deprivation and Enrichment
Some environments can be described as enriched or deprived.
Deprivation refers to a lack of normal nutrition, stimulation,
comfort, or love. Enrichment exists when an environment is
deliberately made more stimulating, loving, and so forth.
What happens when children suffer severe deprivation? Tragically, a few mistreated children have spent their first years in closets, attics, and other restricted environments. When first discovered, these children are usually mute, retarded, and emotionally
damaged (Wilson, 2003). Fortunately, such extreme deprivation is
unusual. Nevertheless, milder perceptual, intellectual, or emotional deprivation occurs in many families, especially those that
must cope with poverty. Poverty can effect the development of
children in at least two ways (Sobolewski & Amato, 2005). First,
poor parents may not be able to give their children needed
resources such as nutritious meals, health care, or learning materials (Bradley & Corwyn, 2002). As a result, impoverished children
tend to be sick more often, their cognitive development lags, and
they do poorly at school. Second, the stresses of poverty can also
be hard on parents, leading to marriage problems, less positive
parenting, and poorer parent-child relationships. The resulting
emotional turmoil can damage a child’s socioemotional development. In the extreme, it may increase the risk of mental illness and
delinquent behavior (Bradley & Corwyn, 2002).
bridges
Adults experience a number of disruptive effects when they
are deprived of perceptual stimulation. See Chapter 6,
page 198, for details.
Adults who grew up in poverty often remain trapped in a
vicious cycle of continued poverty. Because one in seven American
families fall below the poverty line, this grim reality plays itself out
in millions of American homes every day (Sobolewski & Amato,
2005).
Can an improved environment enhance development? To answer
this question, psychologists have created enriched environments
that are especially novel, complex, and stimulating. Enriched environments may be the “soil” from which brighter children grow. To
illustrate, let’s consider the effects of raising rats in a sort of “rat
wonderland.” The walls of their cages were decorated with colorful patterns, and each cage was filled with platforms, ladders, and
cubbyholes. As adults, these rats were superior at learning mazes.
In addition, they had larger, heavier brains, with a thicker cortex
(Benloucif, Bennett, & Rosenzweig, 1995). Of course, it’s a long
leap from rats to people, but an actual increase in brain size is
impressive. If extra stimulation can enhance the “intelligence” of a
lowly rat, it’s likely that human infants also benefit from enrichment. Many studies have shown that enriched environments
improve abilities or enhance development. It would be wise for
Tom and Olivia to make a point of nourishing Samantha’s mind,
as well as her body (Beeber et al., 2007).
What can parents do to enrich a child’s environment? They can
encourage exploration and stimulating play by paying attention to
what holds the baby’s interest. It is better to “child-proof ” a house
Congenital problems Problems or defects that originate during
prenatal development in the womb.
Genetic disorders Problems caused by defects in the genes or by
inherited characteristics.
Teratogen Radiation, a drug, or other substance capable of altering
fetal development in nonheritable ways that cause birth defects.
Sensitive period During development, a period of increased sensitivity
to environmental influences. Also, a time during which certain events
must take place for normal development to occur.
Deprivation In development, the loss or withholding of normal
stimulation, nutrition, comfort, love, and so forth; a condition of lacking.
Enrichment In development, deliberately making an environment
more stimulating, nutritional, comforting, loving, and so forth.
84
CHAPTER 3
than to strictly limit what a child can touch. There is also value in
actively enriching sensory experiences. Infants are not vegetables.
Babies should be surrounded by colors, music, people, and things
to see, taste, smell, and touch. It makes perfect sense to take them
outside, to hang mobiles over their cribs, to place mirrors nearby,
to play music for them, or to rearrange their rooms now and then.
Children progress most rapidly when they have responsive parents
and stimulating play materials at home (Beeber et al., 2007). In
light of this, it is wise to view all of childhood as a relatively sensitive period (Nelson, 1999).
Reaction Range
One way to visualize the interplay of heredity and environment
is through the concept of reaction range, the limits that one’s
environment places on the effects of heredity ( Figure 3.5). Let’s
suppose that Samantha was born with genes for a normal level
of musical ability. If Samantha grows up in a musically deprived
environment, she might well end up with lower than average adult
musical ability. If Olivia and Tom provide her with an enriched
environment, she will probably have normal, or even above normal, musical ability. While Samantha might not be genetically
capable of becoming a child prodigy, the environment her parents
provide for her will also determine her developmental path.
•
Reciprocal Influences
Nurture often affects the expression of hereditary tendencies
through ongoing reciprocal influences. A good example of such
influences is the fact that growing infants influence their parents’
behavior at the same time they are changed by it.
Newborn babies differ noticeably in temperament. This is the
inherited, physical core of personality. It includes sensitivity, irritability, distractibility, and typical mood (Kagan, 2004). About 40
percent of all newborns are easy children who are relaxed and
agreeable. Ten percent are difficult children who are moody, intense,
and easily angered. Slow-to-warm-up children (about 15 percent)
are restrained, unexpressive, or shy. The remaining children do not
fit neatly into a single category (Chess & Thomas, 1986).
Because of differences in temperament, some babies are more
likely than others to smile, cry, vocalize, reach out, or pay attention. As a result, babies rapidly become active participants in their
own development. For example, Samantha is an easy baby who
smiles frequently and is easily fed. This encourages Olivia to
touch, feed, and sing to Samantha. Olivia’s affection rewards
Samantha, causing her to smile more. Soon, a dynamic relationship blossoms between mother and child. Similarly, good parenting can reciprocally influence a very shy child who, in turn,
becomes progressively less shy.
The reverse also occurs: Difficult children make parents
unhappy and elicit more negative parenting (Parke, 2004). Alternately, negative parenting can turn a moderately shy child into a
very shy one. This suggests that inherited temperaments are
dynamically modified by learning (Kagan, 2005).
A person’s developmental level is his or her current state of
physical, emotional, and intellectual development. To summarize,
three factors combine to determine your developmental level at
any stage of life. These are heredity, environment, and your own
behavior, each tightly interwoven with the others.
KNOWL E DG E B U I L DE R
High
The Interplay of Heredity
and Environment
Reaction Range
Average
Low
IQ Score
RECITE
Deprived
Average
Enriched
Environment
Figure 3.5 The effect of heredity on the development of human traits, such
•as intelligence,
can often be influenced by environmental circumstances. A child
with average genes for intelligence growing up in an average environment might
have an average IQ score as an adult. However, growing up in a deprived environment might result in a somewhat lower IQ score and growing up in an enriched
environment might result in a somewhat higher IQ score. In this way, the environment sets a range within which our hereditary potential is actually expressed. This
range is called the reaction range.
1. Areas of the DNA molecule called genes are made up of dominant
and recessive chromosomes. T or F?
2. Most inherited characteristics can be described as polygenic. T or F?
3. If one parent has a one dominant brown-eye gene and one recessive
blue-eye gene and the other parent has two dominant brown-eye
genes, what is the chance that their child will have blue eyes?
a. 25 percent
b. 50 percent
c. 0 percent
d. 75 percent
4. The orderly sequence observed in the unfolding of many basic
responses can be attributed to ___________________________.
5. “Slow-to-warm-up” children can be described as restrained, unexpressive, or shy. T or F?
6. A ________________________ __________________ is a time of
increased sensitivity to environmental influences.
7. As a child develops there is a continuous ________________________
between the forces of heredity and environment.
REFLECT
Critical Thinking
8. Environmental influences can interact with hereditary programming
in an exceedingly direct way. Can you guess what it is?
Continued
Human Development
avoid falling. You can observe the rooting reflex (reflexive head turning and nursing) by touching Samantha’s cheek. Immediately, she
will turn toward your finger, as if searching for something.
How is such turning adaptive? The rooting reflex helps infants
find a bottle or a breast. Then, when a nipple touches the infant’s
mouth, the sucking reflex (rhythmic nursing) helps her obtain
needed food. Like other reflexes, this is a genetically programmed
action. At the same time, food rewards nursing. Because of this,
babies quickly learn to nurse more actively. Again, we see how the
interplay of nature and nurture alters a baby’s behavior.
The Moro reflex is also interesting. If Samantha’s position is
changed abruptly or if she is startled by a loud noise, she will make
a hugging motion. This reaction has been compared to the movements baby monkeys use to cling to their mothers. (We leave it to
the reader’s imagination to decide if there is any connection.)
Relate
Can you think of clear examples of some ways in which heredity and
environmental forces have combined to affect your development?
How would maturation affect the chances of teaching an infant to eat
with a spoon?
What kind of temperament did you have as an infant? How did it
affect your relationship with your parents or caregivers?
Answers: 1. F 2. T 3. c 4. maturation 5. T 6. sensitive period 7. interaction
8. Environmental conditions sometimes turn specific genes on or off, thus
directly affecting the expression of genetic tendencies (Gottlieb, 1998).
The Newborn — More
Than Meets the Eye
Gateway Question: What can newborn babies do?
At birth the human neonate (NEE-oh-NATE: newborn infant)
will die if not cared for by adults. Newborn babies cannot lift
their heads, turn over, or feed themselves. Does this mean they are
inert and unfeeling? Definitely not! Contrary to common belief,
newborn babies are not oblivious to their surroundings. Infants
have mental capacities that continue to surprise researchers and
delight parents. The emergence of many of these capacities, as
well as a baby’s physical abilities, is closely related to maturation
of the brain, nervous system, and body. Likewise, a baby’s early
emotional life unfolds on a timetable that is largely controlled by
maturation.
Neonates like Samantha can see, hear, smell, taste, and respond
to pain and touch. Although their senses are less acute, babies are
very responsive. Samantha will follow a moving object with her
eyes and will turn in the direction of sounds.
Samantha also has a number of adaptive infant reflexes (Siegler,
DeLoache, & Eisenberg, 2006). To elicit the grasping reflex, press
an object in the neonate’s palm and she will grasp it with surprising
strength. Many infants, in fact, can hang from a raised bar, like little
trapeze artists. The grasping reflex aids survival by helping infants
Perceptual and Cognitive Development
Thirty years ago, many people thought of newborn babies as
mere bundles of reflexes, like the ones just described. But infants
are capable of much more. For example, psychologist Andrew
Meltzoff has found that babies are born mimics (Meltzoff, 2005).
Figure 3.6 shows Meltzoff as he sticks out his tongue, opens his
mouth, and purses his lips at a 20-day-old girl. Will she imitate
him? Videotapes of babies confirm that they imitate adult facial
gestures. As early as 9 months of age, infants can imitate actions a
day after seeing them (Heimann & Meltzoff, 1996). Such mimicry
obviously aids rapid learning in infancy.
How intelligent are neonates? Babies are smarter than many
people think. From the earliest days of life, babies are learning how
the world works. They immediately begin to look, touch, taste,
and otherwise explore their surroundings. From an evolutionary
perspective, a baby’s mind is designed to soak up information,
which it does at an amazing pace (Meltzoff & Prinz, 2002).
In the first months of life, babies are increasingly able to think,
to learn from what they see, to make predictions, and to search for
explanations. For example, Jerome Bruner (1983) observed that
3- to 8-week-old babies seem to understand that a person’s voice
and body should be connected. If a baby hears his mother’s voice
coming from where she is standing, the baby will remain calm. If
her voice comes from a loudspeaker several feet away, the baby will
become agitated and begin to cry.
Another look into the private world of infants can be drawn
from testing their vision. However, such testing is a challenge
because infants cannot talk. Robert Fantz invented a device called
a looking chamber to find out what infants can see and what holds
their attention ( Figure 3.7a). Imagine that Samantha is placed
•
Blend Images/SuperStock
•
Newborn babies display a special interest in the human face. A preference for
seeing their mother’s face develops rapidly and encourages social interactions
between mother and baby.
85
Reaction range The limits environment places on the effects of
heredity.
Temperament The physical core of personality, including emotional
and perceptual sensitivity, energy levels, typical mood, and so forth.
Developmental level An individual’s current state of physical,
emotional, and intellectual development.
86
CHAPTER 3
From A. N. Meltzoff & M. K. Moore, “Imitation of facial and manual gestures by human neonates,” Science, 1977,
198, 75–78.
Figure 3.6 Infant imitation. In the top row of photos,
•Andrew
Meltzoff makes facial gestures at an infant. The bottom
© Rubberball Productions/Getty Images
row records the infant’s responses. Videotapes of Meltzoff and of
tested infants helped ensure objectivity.
(c)
•
(b)
(a)
(d)
Figure 3.7 (a) Eye movements and fixation points of infants are observed in Fantz’s “looking chamber.” (b) Thirteen-week-old infants prefer concentric and curved
patterns like those on the left to nonconcentric and straight-line patterns like those on the right. (c) When they are just days old, infants pay more attention to the faces
of people who are gazing directly at them. (d) Infants look at normal faces longer than at scrambled faces and at both faces longer than designs, like the one on the
right. (Photo a courtesy of David Linton. Drawing from “The Origin of Form Perception” by Robert L. Fantz, Copyright © 1961 by Scientific American, Inc. All rights reserved.)
on her back inside the chamber, facing a lighted area above. Next,
two objects are placed in the chamber. By observing the movements of Samantha’s eyes and the images they reflect, we can tell
what she is looking at. Such tests show that adult vision is about 30
times sharper, but babies can see large patterns, shapes, and edges.
Fantz found that 3-day-old babies prefer complex patterns, such
as checkerboards and bull’s-eyes, to simpler colored rectangles.
Other researchers have learned that infants are excited by circles,
curves, and bright lights ( Figure 3.7b) (Brown, 1990). Immediately after birth, Samantha will be aware of changes in the position
•
of objects (Slater et al., 1991). When she is 6 months old, she will be
able to recognize categories of objects that differ in shape or color.
By 9 months of age she will be able to tell the difference between
dogs and birds or other groups of animals (Mandler & McDonough,
1998). By 1 year of age, she will see as well as her parents (Sigelman
& Rider, 2006). So, there really is a person inside that little body!
Neonates can most clearly see objects about a foot away from
them. It is as if they are best prepared to see the people who love
and care for them (Gopnik, Meltzoff, & Kuhl, 2000). Perhaps
that’s why babies have a special fascination with human faces. Just
Human Development
1. Fetal posture
(newborn)
2. Holds chin up
(1 month)
6. Stands holding furniture
(9 months)
3. Holds chest up
(2 months)
7. Crawls
(10 months)
•
8. Walks if led
(11 months)
4. Sits when supported
(4 months)
9. Stands alone
(11 months)
87
5. Sits alone
(7 months)
10. Walks alone
(12 months)
Figure 3.8 Motor development. Most infants follow an orderly pattern of motor development. Although the order in which children progress is
similar, there are large individual differences in the ages at which each ability appears. The ages listed are averages for American children. It is not unusual
for many of the skills to appear 1 or 2 months earlier than average or several months later (Harris & Liebert, 1991). Parents should not be alarmed if a child’s
behavior differs some from the average.
hours after they are born, babies begin to prefer seeing their mother’s face, rather than a stranger’s (Walton, Bower, & Bower, 1992).
When babies are only 2 to 5 days old, they will pay more attention
to a person who is gazing directly at them, rather than one who is
looking away (Farroni et al., 2004) ( Figure 3.7c).
In a looking chamber, most infants will spend more time looking
at a human face pattern than a scrambled face or a colored oval
( Figure 3.7d). When real human faces are used, infants prefer
familiar faces to unfamiliar faces. However, this reverses at about age
2. At that time, unusual objects begin to interest the child. For
instance, in a classic study Jerome Kagan (1971) showed face masks
to 2-year-olds. Kagan found that the toddlers were fascinated by a
face with eyes on the chin and a nose in the middle of the forehead.
He believes the babies’ interest came from a need to understand why
the scrambled face differed from what they had come to expect.
Such behavior is further evidence that babies actively try to make
sense of their surroundings (Gopnik, Meltzoff, & Kuhl, 2000).
•
•
Motor Development
As we noted previously, the emergence of many basic abilities is closely
tied to maturation, which will be evident, for example, as Samantha
learns motor skills, such as crawling and walking. Of course, the rate
of maturation varies from child to child. Nevertheless, the order of
maturation is almost universal. For instance, Samantha will be able
to sit without support from Tom before she has matured enough to
crawl. Indeed, infants around the world typically sit before they crawl,
crawl before they stand, and stand before they walk ( Figure 3.8).
What about my weird cousin Emo who never crawled? Like cousin
Emo, a few children substitute rolling, creeping, or shuffling for
•
crawling. A very few move directly from sitting to standing and walking. Even so, their motor development is orderly. In general, muscular
control spreads in a pattern that is cephalocaudal (SEF-eh-lo-KODul: from head to toe) and proximodistal (PROK-seh-moe-DIS-tul:
from the center of the body to the extremities). Even if cousin Emo
flunked Elementary Crawling, his motor development followed the
standard top-down, center-outward pattern (Piek, 2006).
Although maturation has a big impact, motor skills don’t simply “emerge.” Samantha must learn to control her actions. When
babies are beginning to crawl or walk, they actively try new movements and select those that work. Samantha’s first efforts may be
flawed — a wobbly crawl or some shaky first steps. However, with
practice, babies “tune” their movements to be smoother and more
effective. Such learning is evident from the very first months of life
(Piek, 2006; Thelen, 2000; Figure 3.9).
•
Emotional Development
Early emotional development also follows a pattern closely tied to
maturation (Panksepp & Pasqualini, 2005). Even the basic emotions
of anger, fear, and joy—which appear to be unlearned—take time
to develop. General excitement is the only emotion newborn infants
clearly express. However, as Tom and Olivia can tell you, a baby’s emotional life blossoms rapidly. One researcher (Bridges, 1932) observed
that all the basic human emotions appear before age 2. Bridges found
that emotions appear in a consistent order and that the first basic split
is between pleasant and unpleasant emotions ( Figure 3.10).
Experts do not yet agree on how quickly emotions unfold
(Oster, 2005). For example, psychologist Carroll Izard thinks that
infants can express several basic emotions as early as 10 weeks of
•
CHAPTER 3
Michael Newman/PhotoEdit
88
•
Figure 3.9 Psychologist Carolyn Rovee-Collier has shown that babies as young
as 3 months old can learn to control their movements. In her experiments, babies
lie on their backs under a colorful crib mobile. A ribbon is tied around the baby’s
ankle and connected to the mobile. Whenever babies spontaneously kick their legs,
the mobile jiggles and rattles. Within a few minutes, infants learn to kick faster. Their
reward for kicking is a chance to see the mobile move (Hayne & Rovee-Collier, 1995).
Affection for children
Affection for adults
Elation
Joy
Delight
Excitement
Distress
Anger
Jealousy
Disgust
Fear
Birth
3
6
9
12
18
24
Months
•
Figure 3.10 The traditional view of infancy holds that emotions are rapidly
differentiated from an initial capacity for excitement. (After K. M. B. Bridges, 1932.
Reprinted by permission of the Society for Research in Child Development, Inc.)
age. When Izard looks carefully at the faces of babies, he sees abundant signs of emotion ( Figure 3.11). The most common infant
expression, he found, is not excitement, but interest — followed by
joy, anger, and sadness (Izard et al., 1995).
If Izard is right, then emotions are “hardwired” by heredity and
related to evolution. Perhaps that’s why smiling is one of a baby’s
most common reactions. Smiling probably helps babies survive by
inviting parents to care for them (Izard et al., 1995).
At first, a baby’s smiling is haphazard. By the age of 8 to 12 months,
however, infants smile more frequently when another person is nearby
(Jones & Hong, 2001). This social smile is especially rewarding to
parents. Infants can even use their social smile to communicate inter-
•
•
Figure 3.11 Infants display many of the same emotional expressions as adults
do. Carroll Izard believes such expressions show that distinct emotions appear within
the first months of life. Other theorists argue that specific emotions come into focus
more gradually, as an infant’s nervous system matures. Either way, parents can expect
to see a full range of basic emotions by the end of a baby’s first year.
est in an object, like the time Samantha smiled when her mother held
up her favorite teddy bear (Venezia et al., 2004). On the other hand,
when new parents see and hear a crying baby, they feel annoyed, irritated, disturbed, or unhappy. Babies the world over, it seems, rapidly
become capable of letting others know what they like and dislike.
(Prove this to yourself sometime by driving a baby buggy.)
With dazzling speed, human infants are transformed from
helpless babies to independent persons. By her third year, Samantha will have a unique personality and she will be able to stand,
walk, talk, and explore. At no other time after birth does development proceed more rapidly. During the same period, Samantha’s
relationships with other people will expand as well. Before we
explore that topic, here’s a chance to review what you’ve learned.
KNOWL E DG E B U I L DE R
The Neonate and Early Maturation
RECITE
1. If an infant is startled, he or she will make movements similar to an
embrace. This is known as the
a. grasping reflex
b. rooting reflex
c. Moro reflex
d. adaptive reflex
2. During infancy, a capacity for imitating others first becomes evident
at about 9 months of age. T or F?
Continued
Human Development
involves becoming aware of oneself as a person. When you look in
a mirror, you recognize the image staring back as your own — except, perhaps, early on Monday mornings. Like many such events,
initial self-awareness depends on maturation of the nervous system.
In a typical test of self-recognition, infants are shown images of
themselves on a TV. Most infants have to be 18 months old before
they recognize themselves (Nielsen & Dissanayake, 2004).
3. After age 2, infants tested in a looking chamber show a marked preference for familiar faces and simpler designs. T or F?
4. General excitement or interest is the clearest emotional response
present in newborn infants, but meaningful expressions of delight
and distress appear soon after. T or F?
5. Neonates display a social smile as early as 10 days after birth. T or F?
REFLECT
Critical Thinking
6. If you were going to test newborn infants to see if they prefer their
own mother’s face to that of a stranger, what precautions would you
take?
Attachment
The real core of social development is found in the emotional
attachment, or close emotional bond, that babies form with their
primary caregivers. To investigate mother–infant relationships,
Harry Harlow separated baby rhesus monkeys from their mothers
at birth. The real mothers were replaced with surrogate (substitute) mothers. Some were made of cold, unyielding wire. Others
were covered with soft terry cloth ( Figure 3.12).
When the infants were given a choice between the two mothers, they spent most of their time clinging to the cuddly terry-cloth
mother. This was true even when the wire mother held a bottle,
making her the source of food. The “love” and attachment displayed toward the cloth replicas was identical to that shown
toward natural mothers. For example, when frightened by rubber
snakes, wind-up toys, and other “fear stimuli,” the infant monkeys
ran to their cloth mothers and clung to them for security. These
classic studies suggest that attachment begins with contact comfort, the pleasant, reassuring feeling infants get from touching
something soft and warm, especially their mother.
Relate
What infant reflexes have you observed? Can you give an example of how
heredity and environment interact during motor development?
To know what a baby is feeling would it be more helpful to be able to
detect delight and distress (Bridges) or joy, anger, and sadness (Izard)?
•
Answers: 1. c 2. F 3. F 4. T 5. F 6. In one study of the preferences of newborns, the hair color and complexion of strangers was matched to that of
the mothers. Also, only the mother’s or stranger’s face was visible during
testing. And finally, a scent was used to mask olfactory (smell) cues so
that an infant’s preference could not be based on the mother’s familiar
odor (Bushnell, Sai, & Mullin, 1989).
Social Development —
Baby, I’m Stuck on You
Gateway Question: Of what significance is a child’s emotional bond
with adults?
Infants begin to develop self-awareness and to become aware of
others at about the same time they first form an emotional bond
with an adult. Each of these developments is an important step
toward entering the social world. Parents are the most important
influences in early social development. Later, playing with other
children begins to extend a child’s social life beyond the family.
Like all humans, babies are social creatures. Their early social
development lays a foundation for relationships with parents, siblings, friends, and relatives. A first basic step into the social world
monkeys become attached to the cloth
“contact-comfort” mother but not to a similar wire mother. This is true even when the
wire mother provides food. Contact comfort
may also underlie the tendency of children
to become attached to inanimate objects,
such as blankets or stuffed toys. However, a
study of 2- to 3-year-old blanket-attached
children found that they were no more insecure than others (Passum, 1987). (So maybe
Linus is okay after all.)
Social smile Smiling elicited by social stimuli, such as seeing a parent’s
face.
Social development The development of self-awareness, attachment
to parents or caregivers, and relationships with other children and
adults.
Emotional attachment An especially close emotional bond that
infants form with their parents, caregivers, or others.
Surrogate mothers A substitute mother (often an inanimate dummy
in animal research).
Contact comfort A pleasant and reassuring feeling human and animal
infants get from touching or clinging to something soft and warm,
usually their mother.
Harry Harlow, U. of WI Primate Laboratory
3.12 An infant monkey clings
•to aFigure
cloth-covered surrogate mother. Baby
Ursula Markus/Photo Researchers, Inc.
A sense of self, or self-awareness, develops at about age 18 months. Before children develop self-awareness, they do not recognize their own image in a mirror.
Typically, they think they are looking at another child. Some children hug the child
in the mirror or go behind it looking for the child they see there (Lewis, 1995).
89
90
CHAPTER 3
Figure 3.13 In the United
•States,
about two thirds of all chil-
Most parents are familiar with the storm of
crying that sometimes occurs when babies
are left alone at bedtime. Bedtime distress
can be a mild form of separation anxiety.
As many parents know, it is often eased
by the presence of “security objects,” such
as a stuffed animal or favorite blanket
(Donate-Bartfield & Passman, 2004).
dren from middle-class families are
securely attached. About 1 child
in 3 is insecurely attached.
(Percentages are approximate.)
Attachment Category
5% Unclassified
10% Ambivalent
(From Kaplan, 1998.)
Michael Newman/PhotoEdit
22% Avoidant
There is a sensitive period (roughly the first year of life) during
which attachment must occur for optimal development. Mothers
usually begin to feel attached to their baby before birth. For their
part, as babies mature, they become more and more capable of bonding with their mothers. For the first few months, babies respond
more or less equally to everyone. By 2 or 3 months, most babies prefer
their mothers to strangers. By around 7 months, babies generally
become truly attached to their mothers, crawling after her if they can.
Shortly thereafter they also begin to form attachments to other people as well, such as father, grandparents, or siblings (Sigelman &
Rider, 2006). Returning to Samantha’s story, we find that attachment
keeps her close to Olivia, who provides safety, stimulation, and a
secure “home base” from which Samantha can go exploring.
A direct sign that an emotional bond has formed appears
around 8 to 12 months of age. At that time Samantha will display
separation anxiety (crying and signs of fear) when she is left alone
or with a stranger. Mild separation anxiety is normal. When it is
more intense, it may reveal a problem. At some point in their lives,
about 1 in 20 children suffer from separation anxiety disorder
(Dick-Niederhauser & Silverman, 2006). These children are miserable when they are separated from their parents, whom they
cling to or constantly follow. Some fear that they will get lost and
never see their parents again. Many refuse to go to school, which
can be a serious handicap. Children tend to grow out of the disorder (Kearney et al., 2003), but if separation anxiety is intense or
lasts for more than a month, parents should seek professional help
for their child (Masi, Mucci, & Millepiedi, 2001).
Attachment Quality
According to psychologist Mary Ainsworth (1913–1999), the quality of attachment is revealed by how babies act when their mothers
return after a brief separation. Infants who are securely attached
have a stable and positive emotional bond. They are upset by the
mother’s absence and seek to be near her when she returns. Insecureavoidant infants have an anxious emotional bond. They tend to
turn away from the mother when she returns. Insecure-ambivalent
attachment is also an anxious emotional bond. In this case, babies
have mixed feelings: They both seek to be near the returning mother
and angrily resist contact with her ( Figure 3.13).
•
63% Secure
Attachment can have lasting effects. Infants who are securely
attached at the age of 1 year show more resiliency, curiosity,
problem-solving ability, and social skill in preschool (Collins &
Gunnar, 1990). In contrast, attachment failures can be quite damaging. Consider, for example, the plight of children raised in
severely overcrowded Romanian orphanages (Wilson, 2003).
These children got almost no attention from adults for the first
year or two of their lives. Some have now been adopted by American and Canadian families, but many are poorly attached to their
new parents. Some, for instance, will wander off with strangers;
they are anxious and remote, and they don’t like to be touched or
make eye contact with others (O’Conner et al., 2003). In short, for
some children, a lack of affectionate care early in life leaves a lasting emotional impact well into adulthood. (See “What’s Your
Attachment Style?”)
Promoting Secure Attachment
The key to secure attachment is a mother who is accepting and
sensitive to her baby’s signals and rhythms. Poor attachment occurs
when a mother’s actions are inappropriate, inadequate, intrusive,
overstimulating, or rejecting. An example is the mother who tries to
play with a drowsy infant or who ignores a baby who is looking at
her and vocalizing. The link between sensitive caregiving and secure
attachment appears to apply to all cultures (Posada et al., 2002).
What about attachment to fathers? Fathers of securely attached
infants tend to be outgoing, agreeable, and happy in their marriage. In general, a warm family atmosphere — one that includes
sensitive mothering and fathering — produces secure children
(Belsky, 1996; Gomez & McLaren, 2007).
Day Care
Does commercial day care interfere with the quality of attachment? It
depends on the quality of day care. Overall, high-quality day care
does not adversely affect attachment to parents (National Institute
of Child Health and Human Development, 1999). In fact, highquality day care can actually improve children’s social and mental
skills (Mercer, 2006). Children in high-quality day care tend to
have better relationships with their mothers and fewer behavior
problems. They also have better cognitive skills and language abilities (Burchinal et al., 2000; Vandell, 2004).
However, all the positive effects just noted are reversed for lowquality day care. Low-quality day care is risky and it may weaken
Human Development
91
D ISCOVERI N G P S Y CH OL O G Y
What’s Your Attachment Style?
Do our first attachments continue to affect
us as adults? Some psychologists believe
they do, by influencing how we relate to
friends and lovers (Bridges, 2003; Sroufe et
al., 2005). Read the following statements
and see which best describes your adult
relationships.
SECURE ATTACHMENT STYLE
In general, I think most other people are well
intentioned and trustworthy.
I find it relatively easy to get close to others.
I am comfortable relying on others and
having others depend on me.
I don’t worry much about being abandoned
by others.
I am comfortable when other people want to
get close to me emotionally.
AVOIDANT ATTACHMENT STYLE
I tend to pull back when things don’t go well
in a relationship.
I am somewhat skeptical about the idea of
true love.
I have difficulty trusting my partner in a romantic relationship.
Other people tend to be too eager to seek
commitment from me.
I get a little nervous if anyone gets too close
emotionally.
AMBIVALENT ATTACHMENT STYLE
I have often felt misunderstood and unappreciated in my romantic relationships.
My friends and lovers have been somewhat
unreliable.
I love my romantic partner but I worry that
she or he doesn’t really love me.
attachment. Poor-quality day care can even create behavior problems that didn’t exist beforehand (Pierrehumbert et al., 2002).
Parents are wise to carefully evaluate and monitor the quality of
day care their children receive.
What should parents look for when they evaluate the quality of
child care? Parents seeking quality should insist on at least the following: a small number of children per caregiver; small overall
group size (12 to 15); trained caregivers; minimal staff turnover;
and stable, consistent care (Howes, 1997). (Also, avoid any childcare center with the words zoo, menagerie, or stockade in its name.)
Attachment and Affectional Needs
A baby’s affectional needs (needs for love and affection) are
every bit as important as more obvious needs for food, water, and
physical care. All things considered, creating a bond of trust and
affection between the infant and at least one other person is a key
event during the first year of life. Parents are sometimes afraid of
“spoiling” babies with too much attention, but for the first year or
two this is nearly impossible. In fact, a later capacity to experience
warm and loving relationships may depend on it.
Parental Influences —
Life with Mom and Dad
Gateway Question: How important are parenting styles?
From the first few years of life, when caregivers are the center of a
child’s world, through to adulthood, the style and quality of mothering and fathering are very important.
I would like to be closer to my romantic
partner, but I’m not sure I trust her or
him.
Do any of the preceding statements
sound familiar? If so, they may describe your
adult attachment style. Most adults have a
secure attachment style that is marked by
caring, supportiveness, and understanding.
However, it’s not unusual to have an avoidant attachment style that reflects a tendency
to resist intimacy and commitment to others
(Collins et al., 2002). An ambivalent attachment style is marked by mixed feelings about
love and friendship (Tidwell, Reis, & Shaver,
1996). Do you see any similarities between
your present relationships and your attachment experiences as a child?
Parenting Styles
Psychologist Diana Baumrind (1991, 2005) has studied the effects
of three major parental styles, which are identifiable patterns of
parental caretaking and interaction with children. See if you recognize the styles she describes.
Authoritarian parents enforce rigid rules and demand strict
obedience to authority. Typically they view children as having few
rights but adult-like responsibilities. The child is expected to stay
out of trouble and to accept, without question, what parents
regard as right or wrong. (“Do it because I say so.”) The children
of authoritarian parents are usually obedient and self-controlled.
But they also tend to be emotionally stiff, withdrawn, apprehensive, and lacking in curiosity.
Separation anxiety Distress displayed by infants when they are
separated from their parents or principal caregivers.
Secure attachment A stable and positive emotional bond.
Insecure-avoidant attachment An anxious emotional bond marked
by a tendency to avoid reunion with a parent or caregiver.
Insecure-ambivalent attachment An anxious emotional bond
marked by both a desire to be with a parent or caregiver and some
resistance to being reunited.
Affectional needs Emotional needs for love and affection.
Parental styles Identifiable patterns of parental caretaking and
interaction with children.
Authoritarian parents Parents who enforce rigid rules and demand
strict obedience to authority.
92
CHAPTER 3
Overly permissive parents give little guidance, allow too much
freedom, or don’t hold children accountable for their actions.
Typically, the child has rights similar to an adult’s but few responsibilities. Rules are not enforced, and the child usually gets his or
her way. (“Do whatever you want.”) Permissive parents tend to
produce dependent, immature children who misbehave frequently.
Such children are aimless and likely to “run amok.”
Baumrind describes authoritative parents as those who supply
firm and consistent guidance, combined with love and affection.
Such parents balance their own rights with those of their children.
They control their children’s behavior in a caring, responsive, nonauthoritarian way. (“Do it for this reason.”) Effective parents are
firm and consistent, not harsh or rigid. In general, they encourage
the child to act responsibly, to think, and to make good decisions.
This style produces children who are resilient (good at bouncing
back after bad experiences) and develop the strengths they need to
thrive even in difficult circumstances (Kim-Cohen et al., 2004;
Masten, 2001). The children of authoritative parents are competent,
self-controlled, independent, assertive, and inquiring. They know
how to manage their emotions and use positive coping skills (Eisenberg et al., 2003; Lynch et al., 2004). To read more about effective
parenting, see this chapter’s Psychology in Action section.
It might seem that the father’s role as a playmate makes him
less important. Not so. Samantha’s playtime with Tom is actually
very valuable. From birth onward, fathers pay more visual attention to children than mothers do. Fathers are much more tactile
(lifting, tickling, and handling the baby), more physically arousing (engaging in rough-and-tumble play), and more likely to
engage in unusual play (imitating the baby, for example) (Crawley & Sherrod, 1984; Paquette et al., 2003). In comparison,
mothers speak to infants more, play more conventional games
(such as peekaboo), and, as noted, spend much more time in
caregiving. Young children who spend a lot of time playing with
their fathers tend to be more competent in many ways (TamisLeMonda et al., 2004).
Overall, fathers can be as affectionate, sensitive, and responsive as mothers are. Nevertheless, infants and children tend to
get very different views of males and females. Females, who offer
comfort, nurturance, and verbal stimulation, tend to be close at
hand. Males come and go, and when they are present, action,
exploration, and risk-taking prevail. It’s no wonder, then, that
the parental styles of mothers and fathers have a major impact on
children’s gender role development (Lindsay, Mize, & Pettit,
1997; Videon, 2005).
Maternal and Paternal Influences
Don’t mothers and fathers parent differently? Yes. Although maternal influences (all the effects a mother has on her child) generally
have a greater impact, fathers do make a unique contribution to
parenting (Santrock, 2007). Although fathers are spending more
time with their children, mothers still do most of the nurturing
and caretaking, especially of young children (Craig, 2006).
Studies of paternal influences (the sum of all effects a father
has on his child) reveal that fathers are more likely to play with
their children and tell them stories. In contrast, mothers are typically responsible for the physical and emotional care of their children ( Figure 3.14).
•
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Fathers
Mothers
Fathering typically makes a contribution to early development that differs in
emphasis from mothering.
3.14 Mother-child and father-child interactions. This graph shows
•whatFigure
occurred on routine days in a sample of more than 1,400 Australian homes.
Mothers spend about twice as long each day on child care, compared with fathers.
Further, mothers spend more time on physical and emotional care (such as feeding,
bathing, soothing) than on interactive care (such as playing, reading, activities);
fathers show the reverse pattern. Finally, mothers spend more time on travel (for
instance, driving children to sports or music lessons), communication (such as talking to teachers about their children), and passive care (supervising children while
they play). (Adapted from Craig, 2006.)
93
Human Development
Ethnic Differences: Four Flavors of Parenting
Do ethnic differences in parenting affect children in distinctive ways?
Diana Baumrind’s work provides a good overall summary of the
effects of parenting. However, her conclusions are probably most
valid for families whose roots lie in Europe. Child rearing in other
ethnic groups often reflects different customs and beliefs. Cultural
differences are especially apparent with respect to the meaning
attached to a child’s behavior. Is a particular behavior “good” or
“bad”? Should it be encouraged or discouraged? The answer will
depend greatly on parents’ cultural values (Leyendecker et al.,
2005).
Making generalizations about groups of people is always risky.
Nevertheless, some typical differences in child-rearing patterns
have been observed in North American ethnic communities
(Kaplan, 1998; Parke, 2004).
expect respect, obedience, self-control, and self-discipline from
their children.
Arab-American Families
In Middle Eastern cultures, children are expected to be polite,
obedient, disciplined, and conforming. Punishment generally consists of spankings, teasing, or shaming in front of others. ArabAmerican fathers tend to be strong authority figures who demand
obedience so that the family will not be shamed by a child’s bad
behavior. Success, generosity, and hospitality are highly valued in
Arab-American culture. The pursuit of family honor encourages
hard work, thrift, conservatism, and educational achievement. The
welfare of the family is emphasized over individual identity. Thus,
Arab-American children are raised to respect their parents, members of their extended family, and other adults as well (Erickson &
Al-Timimi, 2001; Medhus, 2001).
African-American Families
Traditional African-American values emphasize loyalty and interdependence among family members, security, developing a positive identity, and not giving up in the face of adversity. AfricanAmerican parents typically stress obedience and respect for elders
(Dixon, Graber, & Brooks-Gunn, 2008). Child discipline tends to
be fairly strict (Parke, 2004), but many African-American parents
see this as a necessity, especially if they live in urban areas where
safety is a concern. Self-reliance, resourcefulness, and an ability
to take care of oneself in difficult situations are also qualities that
African-American parents seek to promote in their children.
Hispanic Families
Asian-American Families
Asian cultures tend to be group oriented, and they emphasize
interdependence among individuals. In contrast, Western cultures value individual effort and independence. This difference is
often reflected in Asian-American child-rearing practices (Chao
& Tseng, 2002). Asian-American children are taught that their
behavior can bring either pride or shame to the family. Therefore,
they are obliged to set aside their own desires when the greater
good of the family is at stake (Parke, 2004). Parents tend to act as
teachers who encourage hard work, moral behavior, and achievement. For the first few years, parenting is lenient and permissive.
However, after about age 5, Asian-American parents begin to
Steven J. Gold
Like African-American parents, Hispanic parents tend to have
relatively strict standards of discipline (Dixon, Graber, & BrooksGunn, 2008). They also place a high value on family values, family pride, and loyalty. Hispanic families are typically affectionate
and indulgent toward younger children. However, as children
grow older, they are expected to learn social skills and to be calm,
obedient, courteous, and respectful. In fact, such social skills may
be valued more than cognitive skills (Delgado & Ford, 1998). In
addition, Hispanic parents tend to stress cooperation more than
competition. Such values can put Hispanic children at a disadvantage in highly competitive, European-American culture.
In other ethnic communities, norms for effective parenting often differ in subtle
ways from parenting styles in Euro-American culture.
Overly permissive parents Parents who give little guidance, allow too
much freedom, or do not require the child to take responsibility.
Authoritative parents Parents who supply firm and consistent
guidance combined with love and affection.
Maternal influences The aggregate of all psychological effects
mothers have on their children.
Paternal influences The aggregate of all psychological effects fathers
have on their children.
CHAPTER 3
Implications
Child rearing is done in a remarkable variety of ways around the
world. In fact, many of the things we do in North America, such
as forcing young children to sleep alone, would be considered odd
or wrong in other cultures. In the final analysis, parenting can only
be judged if we know what culture or ethnic community a child is
being prepared to enter (Leyendecker et al., 2005).
K NOW LED G E B U I L D E R
Social Development in Childhood
RECITE
1. Clear signs of self-awareness or self-recognition are evident in most
infants by the time they reach 8 months of age. T or F?
2. The development of separation anxiety in an infant corresponds to
the formation of an attachment to parents. T or F?
3. High-quality day care can actually improve children’s social and
mental skills. T or F?
4. Fathers are more likely to act as playmates for their children, rather
than caregivers. T or F?
5. According to Diana Baumrind’s research, effective parents are
authoritarian in their approach to their children’s behavior. T or F?
6. Asian-American parents tend to be more individually oriented than
parents whose ethnic roots are European. T or F?
REFLECT
Critical Thinking
7. Can you think of another way to tell if infants have self-awareness?
8. Can emotional bonding begin before birth?
Relate
Do you think that your experiences as a child, such as your early attachment pattern, really affect your life as an adult? Can you think of any
examples from your own life?
Do you know any parents who have young children and who are
authoritarian, permissive, or authoritative? What are their children like?
Do you think parenting depends on ethnicity? If so, why? If not,
why not?
Language Development —
Fast-Talking Babies
Gateway Question: How do children acquire language?
There’s something almost miraculous about a baby’s first words. As
infants, how did we manage to leap into the world of language? Even
a quick survey like this one reveals that both maturation (nature)
and social development (nurture) provide a foundation for language
learning. Let’s begin with a quick survey of language development.
Language development is closely tied to maturation (Carroll,
2008; Gleason, 2005). As every parent knows, babies can cry from
birth on. By 1 month of age they use crying to gain attention. Typically, parents can tell if an infant is hungry, angry, or in pain from the
tone of the crying (Kaplan, 1998). Around 6 to 8 weeks of age, babies
begin cooing (the repetition of vowel sounds such as “oo” and “ah”).
By 7 months of age, Samantha’s nervous system will mature
enough to allow her to grasp objects, smile, laugh, sit up, and babble.
In the babbling stage, the consonants b, d, m, and g are combined
with the vowel sounds to produce meaningless language sounds:
dadadadada or bababa. At first, babbling is the same around the
world. But soon, the language spoken by parents begins to have an
influence. That is, Japanese babies start to babble in a way that
sounds like Japanese, Mexican babies babble in Spanish-like sounds,
and so forth (Gopnik, Meltzoff, & Kuhl, 2000; Kuhl, 2004).
At about 1 year of age, children respond to real words such as no
or hi. Soon afterward, the first connection between words and
objects forms, and children may address their parents as “Mama” or
“Dada.” By age 18 months to 2 years, Samantha’s vocabulary may
include a hundred words or more. At first there is a single-word
stage, during which children use one word at a time, such as “go,”
“juice,” or “up.” Soon after, words are arranged in simple two-word
sentences called telegraphic speech: “Want-Teddy,” “Mama-gone.”
Language and the Terrible Twos
At about the same time that children begin to put two or three
words together they become much more independent. Two-yearolds understand some of the commands parents make, but they are
not always willing to carry them out. A child like Samantha may
assert her independence by saying “No drink,” “Me do it,” “My cup,
my cup,” and the like. It can be worse, of course. A 2-year-old may
look at you intently, make eye contact, listen as you shout “No,
no,” and still pour her juice on the cat.
© Baby Blues Partnership. Reprinted with special
permission of King Features Syndicate.
94
Answers: 1. F 2. T 3. T 4. T 5. F 6. F 7. Another successful method is to
secretly rub a spot of rouge on an infant’s nose. The child is then placed
in front of a mirror. The question is, Will the child touch the red spot,
showing recognition of the mirror image as his or her own? The probability that a child will do so jumps dramatically during the second year.
8. It certainly can for parents. When a pregnant woman begins to feel
fetal movements, she becomes aware that a baby is coming to life inside
of her. Likewise, prospective parents who hear a fetal heartbeat at the
doctor’s office or see an ultrasound image of the fetus begin to become
emotionally attached to the unborn child (Santrock, 2007).
Human Development
95
During their second year, children
become increasingly capable of mischief and temper tantrums. Thus,
calling this time “the terrible twos” is
not entirely inappropriate. One-yearolds can do plenty of things parents
don’t want them to do. However, it’s
usually 2-year-olds who do things
because you don’t want them to
(Gopnik, Meltzoff, & Kuhl, 2000).
Perhaps parents can take some comfort in knowing that a stubborn, negative 2-year-old is simply becoming
85
50
20
Medium high positive
Neutral attention
Avert
more independent. When Samantha
Figure 3.15 Infant engagement scale. These samples from a 90-point scale show various levels of infant engageis 2, Olivia and Tom would be wise to
ment, or attention. Babies participate in prelanguage “conversations” with parents by giving and withholding attention
remember that “this, too, shall pass.” and by smiling, gazing, or vocalizing. (From Beebe et al., 1982.)
After age 2, the child’s comprehension and use of words takes a dramatic leap forward. From this
to communicate long before the child can speak. A readiness to
point on, vocabulary and language skills grow at a phenomenal
interact socially with parents may be as important as innate lanrate (Fernald, Perfors, & Marchman, 2006). By first grade, Samanguage recognition. The next section explains why.
tha will be able to understand around 8,000 words and use about
Early Communication
4,000. She will have truly entered the world of language.
How do parents communicate with infants before they can talk? Parents go to a great deal of trouble to get babies to smile and vocalize
The Roots of Language
( Figure 3.15). In doing so, they quickly learn to change their
What accounts for this explosion of language development? Linguist
actions to keep the infant’s attention, arousal, and activity at optimal
Noam Chomsky (1975, 1986) has long claimed that humans have
levels. A familiar example is the “I’m-Going-to-Get-You Game.” In
a biological predisposition or hereditary readiness to develop
it, the adult says, “I’m gonna getcha . . . . I’m gonna getcha . . . .
language. According to Chomsky, language patterns are inborn,
I’m gonna getcha . . . . Gotcha!” Through such games, adults and
much like a child’s ability to coordinate walking. If such inborn
babies come to share similar rhythms and expectations (Carroll,
language recognition does exist, it may explain why children
2008). Soon a system of shared signals is created, including toucharound the world use a limited number of patterns in their first
ing, vocalizing, gazing, and smiling. These help lay a foundation
sentences. Typical patterns include (Mussen et al., 1979):
for later language use (Tamis-LeMonda, Bornstein, & Baumwell,
2001). Specifically, signals establish a pattern of “conversational”
Identification:
“See kitty.”
turn-taking (alternate sending and receiving of messages).
Nonexistence:
“Allgone milk.”
•
•
Possession:
Agent-Action:
Negation:
Question:
“My doll.”
“Mama give.”
“Not ball.”
“Where doggie?”
Does Chomsky’s theory explain why language develops so rapidly?
It is certainly part of the story. But many psychologists feel that
Chomsky underestimates the importance of learning (Tomasello,
2003) and the social contexts that shape language development
(Hoff, 2006). Psycholinguists (specialists in the psychology of language) have shown that imitation of adults and rewards for correctly using words (as when a child asks for a cookie) are an important part of language learning. Also, babies actively participate in
language learning by asking questions, such as “What dis?”
(Domingo & Goldstein-Alpern, 1999).
When a child makes a language error, parents typically repeat
the child’s sentence with needed corrections (Bohannon & Stanowicz, 1988; Hoff, 2006) or ask a clarifying question to draw the
child’s attention to the error (Saxton, Houston-Price, & Dawson,
2005). More important is the fact that parents and children begin
Olivia
“Oh what a nice little smile!”
“Yes, isn’t that nice?”
“There.”
“There’s a nice little smile.”
“Well, pardon you!”
“Yes, that’s better, isn’t it?”
“Yes.”
“Yes.”
“What’s so funny?”
Samantha
(smiles)
(burps)
(vocalizes)
(smiles)
Biological predisposition The presumed hereditary readiness of
humans to learn certain skills, such as how to use language, or a
readiness to behave in particular ways.
Signal In early language development, any behavior, such as touching,
vocalizing, gazing, or smiling, that allows nonverbal interaction and
turn-taking between parent and child.
96
CHAPTER 3
From the outside, such exchanges may look meaningless. In reality, they represent real communication. Samantha’s vocalizations
and attention provide a way of interacting emotionally with Olivia
and Tom. Infants as young as 4 months engage in vocal turn-taking
with adults ( Jaffe et al., 2001). The more children interact with
parents, the faster they learn to talk and the faster they learn thinking abilities (Dickinson & Tabors, 2001; Hoff & Tian, 2005). One
study found that 6-week-old babies gaze at an adult’s face in rhythm
with the adult’s speech (Crown et al., 2002). Unmistakably, social
relationships contribute to early language learning (Hoff, 2006).
Parentese
When they talk to infants, parents use an exaggerated pattern of
speaking called motherese or parentese. Typically, they raise their
tone of voice; use short, simple sentences; repeat themselves more;
and use frequent gestures (Gogate, Bahrick, & Watson, 2000).
They also slow their rate of speaking and use exaggerated voice
inflections: “Did Samantha eat it A-L-L UP?”
What is the purpose of such changes? Parents are apparently trying to help their children learn language (Soderstrom, 2007).
When a baby is still babbling, parents tend to use long, adult-style
sentences. But as soon as the baby says its first word they switch to
parentese. By the time babies are 4 months old they prefer parentese over normal speech (Cooper et al., 1997).
In addition to being simpler, parentese has a distinct “musical”
quality (Trainor & Desjardins, 2002). No matter what language
mothers speak, the melodies, pauses, and inflections they use to
comfort, praise, or give warning are universal. Psychologist Anne
Fernald has found that mothers of all nations talk to their babies
with similar changes in pitch. For instance, we praise babies with a
rising, then falling pitch (“BRA-vo!” “GOOD girl!”). Warnings
are delivered in a short, sharp rhythm (“Nein! Nein!” “Basta!
Basta!” “Not! Dude!”). To give comfort, parents use low, smooth,
drawn-out tones (“Oooh poor baaa-by,” “Oooh pobrecito”). A
high-pitched, rising melody is used to call attention to objects
(“See the pretty BIRDIE?”) (Fernald, 1989).
Parentese helps parents get babies’ attention, communicate
with them, and teach them language (Thiessen, Hill, & Saffran,
2005). Later, as a child’s speaking improves, parents tend to adjust
their speech to the child’s language ability. Especially from 18
months to 4 years of age, parents seek to clarify what a child says
and prompt the child to say more.
In summary, some elements of language are innate. Nevertheless, our inherited tendency to learn language does not determine
if we will speak English or Vietnamese, Spanish or Russian. Environmental forces also influence whether a person develops simple
or sophisticated language skills. The first 7 years of life are a sensitive period in language learning (Eliot, 1999). Clearly, a full flowering of speech requires careful cultivation.
KNOWL E DG E B U I L DE R
Language Development in Childhood
RECITE
1. The development of speech and language usually occurs in which
order?
a. crying, cooing, babbling, telegraphic speech
b. cooing, crying, babbling, telegraphic speech
c. babbling, crying, cooing, telegraphic speech
d. crying, babbling, cooing, identification
2. Simple two-word sentences are characteristic of ________________
_______________ speech.
3. Noam ________________________ has advanced the idea that language acquisition is built on innate patterns.
4. Prelanguage turn-taking and social interactions would be of special
interest to a psycholinguist. T or F?
5. The style of speaking known as ______________________________
is higher in pitch and has a musical quality.
REFLECT
As with motherese, parents use a distinctive style when singing to an infant.
Even people who speak another language can tell if a tape-recorded song was
sung to an infant or an adult. Likewise, lullabies remain recognizable when electronic filtering removes words (Trehub et al., 1993a, 1993b).
Relate
In order, see if you can name and imitate the language abilities you had
as you progressed from birth to age 2 years. Now see if you can label and
imitate some basic elements of parentese.
In your own words, state at least one argument for and against
Chomsky’s view of language acquisition.
You are going to spend a day with a person who speaks a different
language than you do. Do you think you would be able to communicate
with the other person? How does this relate to language acquisition?
Answers: 1. a 2. telegraphic 3. Chomsky 4. T 5. Parentese or motherese
6. Children in professional homes receive many educational benefits that
are less common in welfare homes. Yet, even when such differences are
taken into account, brighter children tend to come from richer language
environments (Hart & Risley, 1999).
Gary Conner/Index Stock Imagery/Photolibrary
Critical Thinking
6. The children of professional parents hear more words per hour than the
children of welfare parents, and they also tend to score higher on tests
of mental abilities. How else could their higher scores be explained?
Human Development
97
eyes. Is it still there? How do you know? As an adult, you can
keep an image of the object in your “mind’s eye.” According to
Piaget, newborn babies cannot create internal representations such
as mental images. As a result, they lack object permanence, an
understanding that objects continue to exist when they are out of
sight.
Cognitive Development —
Think Like a Child
Gateway Question: How do children learn to think?
Now that we have Samantha talking, let’s move on to a broader view
of intellectual development. Jean Piaget ( Jahn pea-ah-ZHAY)
provided some of the first great insights into how children develop
thinking abilities when he proposed that children’s cognitive skills
progress through a series of maturational stages. Also, many psychologists have become interested in how children learn the intellectual skills valued by their culture. Typically, children do this
with guidance from skilled “tutors” (parents and others).
How different is a child’s understanding of the world from that of
an adult? According to the Swiss psychologist and philosopher
Jean Piaget (1951, 1952), their thinking is, generally speaking, less
abstract. They tend to base their understanding on particular
examples and objects they can see or touch. Also, children use
fewer generalizations, categories, and principles.
bridges
Concepts and language are other types of internal
representation. See Chapter 9, page 284, for more
information.
Jean Piaget believed that all children mature through a series of
distinct stages in intellectual development. Many of his ideas came
from observing his own children as they solved various thought
problems. (It is tempting to imagine that Piaget’s illustrious career
was launched one day when his wife said to him, “Watch the children for a while, will you, Jean?”)
For this reason, in the first 2 years of life, Samantha’s intellectual development will be largely nonintellectual and nonverbal.
She will be mainly concerned with learning to coordinate information from her senses with her motor movements. But sometime
during their first year, babies begin to actively pursue disappearing
objects. By age 2, they can anticipate the movement of an object
behind a screen. For example, when watching an electric train,
Samantha will look ahead to the end of a tunnel, rather than staring at the spot where the train disappeared.
In general, developments in this stage indicate that the child’s
conceptions are becoming more stable. Objects cease to appear
and disappear magically, and a more orderly and predictable world
replaces the confusing and disconnected sensations of infancy.
Mental Processes
The Preoperational Stage (2–7 Years)
Piaget was convinced that intellect grows through processes he
called assimilation and accommodation. Assimilation refers to
using existing mental patterns in new situations. Let’s say that Benjamin pounds on blocks with his favorite toy, a plastic hammer.
For his birthday Benjamin gets an oversized toy wrench. If he uses
the wrench for pounding, it has been assimilated to an existing
knowledge structure.
In accommodation, existing ideas are modified to fit new
requirements. For instance, a younger child might think that a
dime is worth less than a (larger) nickel. However, as children
begin to spend money, they must
alter their ideas about what “more”
and “less” mean. Thus, new situations are assimilated to existing
ideas, and new ideas are created to
accommodate new experiences.
Piaget’s ideas have deeply
affected our view of children (Feldman, 2004). The following is a
brief summary of what he found.
Close your eyes again. Imagine the room you sleep in. What would
it look like if you were perched on the ceiling? You have now mentally transformed your image of the room. According to Piaget,
even though preoperational children can form mental images or
ideas, they cannot easily transform those images or ideas in their
minds.
Piaget’s Theory of Cognitive Development
Look up from this book until your
attention is attracted to something
else in the room. Now close your
Jean Piaget — philosopher, psychologist, and keen observer of
children.
Assimilation In Piaget’s theory, the application of existing mental
patterns to new situations (that is, the new situation is assimilated to
existing mental schemes).
Accommodation In Piaget’s theory, the modification of existing mental
patterns to fit new demands (that is, mental schemes are changed to
accommodate new information or experiences).
Sensorimotor stage Stage of intellectual development during which
sensory input and motor responses become coordinated.
Farrell Grehan/Corbis
The Sensorimotor Stage
(0–2 Years)
Motherese (or parentese) A pattern of speech used when talking
to infants, marked by a higher-pitched voice; short, simple sentences;
repetition, slower speech; and exaggerated voice inflections.
Object permanence Concept, gained in infancy, that objects continue
to exist even when they are hidden from view.
Preoperational stage Period of intellectual development during
which children begin to use language and think symbolically, yet remain
intuitive and egocentric in their thought.
Transformation The ability to mentally change the shape or form of a
mental image or idea.
98
CHAPTER 3
FogStock LLC/Index Stock Imagery/Photolibrary
Before the age of 6 or 7, children begin to think symbolically
and use language. But the child’s thinking is still very concrete and
intuitive (it makes little use of reasoning and logic). (Do you
remember thinking as a child that the sun and the moon followed
you when you took a walk?).
Let’s visit Samantha at age 5: If you show her a short, wide glass
full of milk and a taller, narrow glass (also full), she will most likely
tell you that the taller glass contains more milk (even if it doesn’t).
Samantha will tell you this even if she watches you pour milk from
the short glass into an empty, tall glass. Older children can easily
mentally reverse the pouring of the milk to see that the shape of
container is irrelevant to the volume of milk it contains. But
Samantha is preoperational; she cannot engage in the mental
operation of transforming the tall glass of milk back into a short,
wide glass. Thus, she is not bothered by the fact that the milk
appears to be transformed from a smaller to a larger amount.
Instead, she responds only to the fact that taller seems to mean
more ( Figure 3.16).
After about age 7, children are no longer fooled by this situation. Perhaps that’s why 7 has been called the “age of reason.” From
age 7 on, we see a definite trend toward more logical, adult-like
thought (Flavell, 1992).
During the preoperational stage, the child is also quite egocentric (unable to take the viewpoint of other people). The child’s ego
seems to stand at the center of his or her world. To illustrate, show
Samantha a two-sided mirror. Then hold it between you and her,
so she can see herself in it. If you ask her what she thinks you can
see, she imagines that you see her face reflected in the mirror,
instead of your own. She cannot mentally transform the view she
sees into the view you must be seeing.
Crossing a busy street can be dangerous for the preoperational child. Because
their thinking is still egocentric, younger children cannot understand why the
driver of a car can’t see them if they can see the car. Children under the age of 7
also cannot consistently judge speeds and distances of oncoming cars. Adults
can easily overestimate the “street smarts” of younger children. It is advisable to
teach children to cross with a light, in crosswalks, or with assistance.
•
Such egocentrism explains why children can seem exasperatingly selfish or uncooperative at times. If Benjamin blocks your
view by standing in front of the TV, he assumes that you can see it
if he can. If you ask him to move so you can see better, he may move
so that he can see better! Benjamin is not being selfish in the ordinary sense. He just doesn’t realize that your view differs from his.
In addition, the child’s use of language is not as sophisticated as
it might seem. Children have a tendency to confuse words with the
objects they represent. If Benjamin calls a toy block a “car” and you
use it to make a “house,” he may be upset. To children, the name of
an object is as much a part of the object as its size, shape, and color.
This seems to underlie a preoccupation with name-calling. To the
preoperational child, insulting words may really hurt. Samantha
was once angered by her older brother. Searching for a way to
retaliate against her larger and stronger foe, she settled on, “You
panty-girdle!” It was the worst thing she could think of saying.
The Concrete Operational Stage (7–11 Years)
Tony Freeman/PhotoEdit
The hallmark of this stage is the ability to carry out mental operations such as reversing thoughts. A 4-year-old boy in the preoperational stage might have a conversation like this (showing what
happens when a child’s thinking lacks reversibility):
•
Figure 3.16 Children under age 7 intuitively assume that a volume of liquid
increases when it is poured from a short, wide container into a taller, thinner one.
This boy thinks the tall container holds more than the short one. Actually each
holds the same amount of liquid. Children make such judgments based on the
height of the liquid, not its volume.
“Do you have a brother?”
“Yes.”
“What’s his name?”
“Sam.”
“Does Sam have a brother?”
“No.”
Reversibility of thought allows children in the concrete operational stage to recognize that if 4 2 8, then 2 4 does, too.
Younger children must memorize each relationship separately.
Human Development
•
The Formal Operations Stage (11 Years and Up)
After about the age of 11, children begin to break away from
concrete objects and specific examples. Thinking is based more
on abstract principles, such as “democracy,” “honor,” or “correlation.” Children who reach this stage can think about their own
thoughts, and they become less egocentric. Older children and
young adolescents also gradually become able to consider hypothetical possibilities (suppositions, guesses, or projections). For
example, if you ask a younger child, “What do you think would
happen if it suddenly became possible for people to fly?” the child
might respond, “People can’t fly.” Older children are better able to
consider such possibilities.
Full adult intellectual ability is attained during the stage of
formal operations. Older adolescents are capable of inductive
and deductive reasoning, and they can comprehend math, physics, philosophy, psychology, and other abstract systems. They
can learn to test hypotheses in a scientific manner. Of course,
not everyone reaches this level of thinking. Also, many adults
can think formally about some topics, but their thinking
becomes concrete when the topic is unfamiliar. This implies
that formal thinking may be more a result of culture and learning than maturation. In any case, after late adolescence, improvements in intellect are based on gaining specific knowledge,
experience, and wisdom, rather than on any leaps in basic thinking capacity.
How can parents apply Piaget’s ideas? Piaget’s theory suggests
that the ideal way to guide intellectual development is to provide
experiences that are only slightly novel, unusual, or challenging.
Remember, a child’s intellect develops mainly through accommodation. It is usually best to follow a one-step-ahead strategy, in
which your teaching efforts are aimed just beyond a child’s current
level of comprehension (Brainerd, 2003).
Parents should avoid forced teaching, or “hothousing,” which is
like trying to force plants to bloom prematurely. Forcing children
to learn reading, math, gymnastics, swimming, or music at an
accelerated pace can bore or oppress them. True intellectual enrichment respects the child’s interests. It does not make the child feel
pressured to perform (Alvino et al., 1996).
For your convenience, Table 3.2 briefly summarizes each
Piagetian stage. To help you remember Piaget’s theory, the table
describes what would happen at each stage if we played a game of
Monopoly with the child. You’ll also find brief suggestions about
how to relate to children in each stage.
•
Piaget Today
Piaget’s theory is a valuable “road map” for understanding how
children think. However, many psychologists are convinced that
Piaget gave too little credit to the effects of the learning environment. For example, children who grow up in villages where pottery is made can correctly answer questions about the conservation
of clay at an earlier age than Piaget would have predicted.
According to learning theorists, children continuously gain
specific knowledge; they do not undergo stage-like leaps in general
mental ability (Siegler, 2004). On the other hand, the growth in
© The New Yorker Collection, May 20, 2006 Barbara Smaller from cartoonbank.com.
All Rights Reserved.
Thus, a preoperational child may know that 4 9 36, without
being able to tell you what 9 4 equals.
The development of mental operations allows mastery of conservation (the concept that mass, weight, and volume remain
unchanged when the shape of objects changes). Children have
learned conservation when they understand that rolling a ball of
clay into a “snake” does not increase the amount of clay. Likewise,
pouring liquid from a tall, narrow glass into a shallow dish does
not reduce the amount of liquid. In each case the volume remains
the same despite changes in shape or appearance. The original
amount is conserved. (See Figure 3.16.)
During the concrete operational stage, children begin to use
concepts of time, space, and number. The child can think logically
about very concrete objects or situations, categories, and principles. Such abilities help explain why children stop believing in
Santa Claus when they reach this stage. Because they can conserve
volume, they realize that Santa’s sack couldn’t possibly hold enough
toys for millions of girls and boys.
99
Intuitive thought Thinking that makes little or no use of reasoning
and logic.
Egocentric thought Thought that is self-centered and fails to consider
the viewpoints of others.
Concrete operational stage Period of intellectual development
during which children become able to use the concepts of time, space,
volume, and number, but in ways that remain simplified and concrete,
rather than abstract.
Conservation In Piaget’s theory, mastery of the concept that the
weight, mass, and volume of matter remains unchanged (is conserved)
even when the shape or appearance of objects changes.
Formal operations stage Period of intellectual development
characterized by thinking that includes abstract, theoretical, and
hypothetical ideas.
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CHAPTER 3
Table 3.2
• Piaget—A Guide for Parents
Piaget
Monopoly Game
Guidelines for Parents
Sensorimotor Stage (0–2 Years)
The stage during which sensory input and
motor responses become coordinated.
The child puts houses, hotels, and dice in her
mouth and plays with “Chance” cards.
Active play with a child is most effective at this stage.
Encourage explorations in touching, smelling, and
manipulating objects. Peekaboo is a good way to
establish the permanence of objects.
The child plays Monopoly, but makes up her own
rules and cannot understand instructions.
Specific examples and touching or seeing things
continues to be more useful than verbal explanations. Learning the concept of conservation may be
aided by demonstrations with liquids, beads, clay,
and other substances.
Concrete Operational Stage (7–11 Years)
The period of cognitive development during
which children begin to use concepts of time,
space, volume, and number, but in ways that
remain simplified and concrete.
The child understands basic instructions and will
play by the rules but is not capable of hypothetical transactions dealing with mortgages, loans,
and special pacts with other players.
Children are beginning to use generalizations, but
they still require specific examples to grasp many
ideas. Expect a degree of inconsistency in the child’s
ability to apply concepts of time, space, quantity,
and volume to new situations.
Formal Operations Stage (11 Years and Up)
The period of intellectual development
marked by a capacity for abstract, theoretical,
and hypothetical thinking.
The child no longer plays the game mechanically;
complex and hypothetical transactions unique to
each game are now possible.
It is now more effective to explain things verbally
or symbolically and to help children master general
rules and principles. Encourage the child to create
hypotheses and to imagine how things could be.
Preoperational Stage (2–7 Years)
The period of cognitive development when
children begin to use language and think
symbolically, yet remain intuitive and
egocentric.
continue to be debated (Feldman, 2004). Where early infancy is
concerned, even Piaget’s observations may need updating. It looks
like Piaget greatly underestimated the mental abilities of infants.
Infant Cognition
7 to 15 years
3 to 6 years
Growth
16 to 20 years
Pruning
•
Figure 3.17 Between the ages of 3 and 6 a tremendous wave of growth
occurs in connections among neurons in the frontal areas of the brain. This corresponds to the time when children make rapid progress in their ability to think
symbolically. Between ages 7 and 15, peak synaptic growth shifts to the temporal
and parietal lobes. During this period children become increasingly adept at using
language, a specialty of the temporal lobes. In the late teens, the brain actively
destroys unneeded connections, especially in the frontal lobes. This pruning of synapses sharpens the brain’s capacity for abstract thinking (Restak, 2001).
connections between brain cells occurs in waves that parallel some
of Piaget’s stages ( Figure 3.17). Thus, the truth may lie somewhere between Piaget’s stage theory and modern learning theory.
On a broad scale, many of Piaget’s observations have held up
well. However, his explanations of childhood thinking abilities
•
What evidence is there that Piaget underestimated infant abilities?
Piaget believed that infants under the age of 1 year cannot think
(use internal representations). Babies, he said, can have no memory of people and objects that are out of sight. Yet, we now know
that infants begin forming representations of the world very early
in life. For example, babies as young as 3 months of age appear to
know that objects are solid and do not disappear when out of view
(Baillargeon, 2004).
Why did Piaget fail to detect the thinking skills of infants? Most
likely, he mistook babies’ limited physical skills for mental incompetence. Piaget’s tests required babies to search for objects or
reach out and touch them. Newer, more sensitive methods are
uncovering abilities Piaget missed. One such method takes advantage of the fact that babies, like adults, act surprised when they see
something “impossible” or unexpected occur. To use this effect,
psychologist Renee Baillargeon (1991, 2004) puts on little “magic
shows” for infants. In her “theater,” babies watch as possible
and impossible events occur with toys or other objects. Some
3-month-old infants act surprised and gaze longer at impossible
events. An example is seeing two solid objects appear to pass
through each other. By the time they are 8 months old, babies can
remember where objects are (or should be) for at least 1 minute
( Figure 3.18).
Piaget believed that abilities like those described in Figure 3.18
emerge only after a long period of sensorimotor development. How-
•
•
Human Development
101
Toy placed
behind
screen
Toy retrieved
3.18 The panels on the left show a possible event, in which an infant watches as a toy is placed behind the right of two screens. After a
•delayFigure
of 70 seconds, the toy is brought into view from behind the right screen. In the two panels on the right, an impossible event occurs. The toy is placed
behind the left screen and retrieved from behind the right. (A duplicate toy was hidden there before testing.) Eight-month-old infants react with surprise
when they see the impossible event staged for them. Their reaction implies that they remember where the toy was hidden. Infants appear to have a capacity for memory and thinking that greatly exceeds what Piaget claimed is possible during the sensorimotor period. (Adapted from Baillargeon et al., 1989.)
ever, it’s clear that babies quickly acquire the capacity to form concepts about the world (Eimas, Quinn, & Cowan, 1994). It looks as
if further study is likely to refine and amend the ideas that grew from
Piaget’s fateful decision to “watch the children for a while.”
Another criticism of Piaget is that he underestimated the
impact of culture on mental development. The next section tells
how Samantha will master the intellectual tools valued by her
culture.
Vygotsky’s Sociocultural Theory
While Piaget stressed the role of maturation in cognitive development, Russian scholar Lev Vygotsky (1896–1934) focused on
the impact of sociocultural factors. Vygotsky’s key insight is that
children’s thinking develops through dialogues with more capable
persons (Vygotsky, 1962, 1978).
How does that relate to intellectual growth? So far, no one has
ever published A Child’s Guide to Life on Earth. Instead, children
must learn about life from various “tutors,” such as parents, teachers, and older siblings. Even if A Child’s Guide to Life on Earth did
exist, we would need a separate version for every culture. It is not
enough for children to learn how to think. They must also learn
specific intellectual skills valued by their culture.
Like Piaget, Vygotsky believed that children actively seek to
discover new principles. However, Vygotsky emphasized that
many of a child’s most important “discoveries” are guided by skillful tutors. Psychologist David Shaffer (2002) offers the following
example:
Annie, a 4-year-old, has just received her first jigsaw puzzle as a birthday present. She attempts to work the puzzle but gets nowhere until her
father comes along, sits down beside her, and gives her some tips. He suggests that it would be a good idea to put together the corners first, points
to the pink area at the edge of one corner piece and says, “Let’s look for
another pink piece.” When Annie seems frustrated, he places two inter-
locking pieces near each other so that she will notice them, and when
Annie succeeds, he offers words of encouragement. As Annie gradually
gets the hang of it, he steps back and lets her work more and more independently. (p. 260)
Interactions like this are most helpful when they take place
within a child’s zone of proximal development.
What did Vygotsky mean by that? The word proximal means
close or nearby. Vygotsky realized that, at any given time, some
tasks are just beyond a child’s reach. The child is close to having
the mental skills needed to do the task, but it is a little too complex
to be mastered alone. However, children working within this zone
can make rapid progress if they receive sensitive guidance from a
skilled partner (LeBlanc & Bearison, 2004). (Notice that this is
similar to the one-step-ahead strategy described earlier.)
Vygotsky also emphasized a process he called scaffolding. A
scaffold is a framework or temporary support. Vygotsky believed
that adults help children learn how to think by “scaffolding,” or
supporting, their attempts to solve problems or discover principles
(Daniels, 2005). To be most effective, scaffolding must be responsive to a child’s needs. For example, as Annie’s father helped her
with the puzzle, he tailored his hints and guidance to match her
evolving abilities. The two of them worked together, step by step,
so that Annie could better understand how to assemble a puzzle.
In a sense, Annie’s father set up a series of temporary bridges that
helped her move into new mental territory. As predicted by
Vygotsky’s theory, the reading skills of 8- to 10-year-old children
Zone of proximal development Refers to the range of tasks a child
cannot yet master alone, but that she or he can accomplish with the
guidance of a more capable partner.
Scaffolding The process of adjusting instruction so that it is responsive
to a beginner’s behavior and supports the beginner’s efforts to
understand a problem or gain a mental skill.
102
CHAPTER 3
are closely related to the amount of verbal scaffolding their mothers provided at ages 3 and 4 (Dieterich et al., 2006).
During their collaborations with others, children learn important cultural beliefs and values. For example, imagine that a boy
wants to know how many baseball cards he has. His mother helps
him stack and count the cards, moving each card to a new stack as
they count it. She then shows him how to write the number on a
slip of paper so he can remember it. This teaches the child not only
about counting, but also that writing is valued in our culture. In
other parts of the world, a child learning to count might be shown
how to make notches on a stick or tie knots in a cord.
Implications
Vygotsky saw that grown-ups play a crucial role in what children
know. As they try to decipher the world, children rely on adults to
help them understand how things work. Vygotsky further noticed
that adults unconsciously adjust their behavior to give children the
information they need to solve problems that interest the child. In
this way, children use adults to learn about their culture and society
(Gopnik, Meltzoff, & Kuhl, 2000; LeBlanc & Bearison, 2004).
K NOW LED GE B U I L D E R
Cognitive Development in Childhood
RECITE
Match each item with one of the following stages.
A. Sensorimotor B. Preoperational C. Concrete operational D. Formal
operations
1. _____ egocentric thought
5. _____ conservation
2. _____ abstract or hypothetical
6. _____ reversibility thought
3. _____ purposeful movement
7. _____ object permanence
4. _____ intuitive thought
8. _____ nonverbal development
9. Assimilation refers to applying existing thought patterns or knowledge to new situations. T or F?
10. Newer methods for testing infant thinking abilities frequently make
note of whether an infant is _____________________________ by
seemingly _____________________________ events.
11. Vygotsky called the process of providing a temporary framework of
supports for learning new mental abilities _____________________
____________.
REFLECT
Critical Thinking
12. Using Piaget’s theory as a guide, at what age would you expect a
child to recognize that a Styrofoam cup has weight?
Relate
You are going to make cookies with children of various ages. See if you
can name each of Piaget’s stages and give an example of what a child in
that stage might be expected to do.
You have been asked to help a child learn to use a pocket calculator
to do simple addition. How would you go about identifying the child’s
zone of proximal development for this task? How would you scaffold the
child’s learning?
Adolescence and Young Adulthood —
The Best of Times, the Worst of Times
Gateway Question: Why is the transition from adolescence to
adulthood especially challenging?
Adolescence and young adulthood is a time of change, youthful
exploration, and exuberance. It can also be a time of worry and
problems, especially in today’s world. It might even be fair to
describe this period as “the best of times, the worst of times.” During adolescence, a person’s identity and moral values come into
sharper focus even as the transition to adulthood is occurring at
ever-later ages.
Adolescence is the culturally defined period between childhood and adulthood. Socially, the adolescent is no longer a child,
yet not quite an adult. Almost all cultures recognize this transitional status. However, the length of adolescence varies greatly
from culture to culture. For example, most 14-year-old girls in
North America live at home and go to school. In contrast, many
14-year-old females in rural villages of many poorer countries are
married and have children. In our culture, 14-year-olds are adolescents. In others, they may be adults.
Is marriage the primary criterion for adult status in North America? No, it’s not even one of the top three criteria. Today, the most
widely accepted standards are (1) taking responsibility for oneself,
(2) making independent decisions, and (3) becoming financially
independent. In practice, this typically means breaking away from
parents by taking a job and setting up a separate residence (Arnett,
2001).
Puberty
Many people confuse adolescence with puberty. However, puberty
is a biological event, not a social status. During puberty, hormonal
changes promote rapid physical growth and sexual maturity. Biologically, most people reach reproductive maturity in the early
teens. Social and intellectual maturity, however, may lie years
ahead. Young adolescents often make decisions that affect their
entire lives, even though they are immature mentally and socially.
The tragically high rates of teenage pregnancy and drug abuse are
prime examples. Despite such risks, most people do manage to
weather adolescence without developing any serious psychological
problems (Steinberg, 2001).
How much difference does the timing of puberty make? For boys,
maturing early is generally beneficial. Typically, it enhances their
self-image and gives them an advantage socially and athletically.
Early-maturing boys tend to be more relaxed, dominant, selfassured, and popular. However, early puberty does carry some
risks because early-maturing boys are also more likely to get into
trouble with drugs, alcohol, and antisocial behavior (Steinberg,
2001).
For girls, the advantages of early maturation are less clear-cut.
In elementary school, fast-maturing girls are less popular and have
poorer self-images, perhaps because they are larger and heavier
than their classmates (Deardorff et al., 2007). By junior high, how-
Answers: 1. B 2. D 3. A 4. B 5. C 6. C 7. A 8. A 9. T 10. surprised, impossible 11. scaffolding 12. Seventy-five percent of 4- to 6-year-olds say that
a Styrofoam cup has no weight after lifting it! Most children judge weight
intuitively (by the way an object feels) until they begin to move into the
concrete operational stage (Smith, Carey, & Wiser, 1985).
Human Development
103
HU M AN D I VERS I T Y
Ethnic Diversity and Identity
Ethnic heritage can have a powerful influence
on personal identity (Weisskirch, 2005). For
adolescents of ethnic descent, the question
is often not just “Who am I?” Rather, it is “Who
am I at home? Who am I at school? Who am I
with friends from my neighborhood?”
As ethnic minorities in America continue
to grow in status and prominence, adolescents are less and less likely to feel rejected
or excluded because of their ethnic heritage
as they try to find their place in society. This
is fortunate since ethnic adolescents have
often faced degrading stereotypes concern-
ing their intelligence, sexuality, social status,
manners, and so forth. The result can be lowered self-esteem and confusion about roles,
values, and personal identity (de las Fuentes
& Vasquez, 1999). At the same time, the
increasingly multicultural nature of contemporary American society raises new questions for adolescents about what it means to
be American (Schwartz, 2008).
In forming an identity, adolescents of
ethnic descent face the question of how
they should think of themselves. Is Lori an
American or a Chinese American or both?
ever, early development includes sexual features. This leads to a
more positive body image, greater peer prestige, and adult approval
(Brooks-Gunn & Warren, 1988). Early-maturing girls tend to date
sooner and are more independent and more active in school. However, like their male counterparts, they are also more often in
trouble at school and more likely to engage in early sex (Flannery
et al., 1993).
As you can see, there are costs and benefits associated with early
puberty. One added cost of early maturation is that it may force
premature identity formation. When Samantha is a teenager and
she begins to look like an adult, she may be treated like an adult.
Is Jaime a Latino, a Chicano, or a Mexican
American? The answer typically depends on
how strongly adolescents identify with their
family and ethnic community. Teens who take
pride in their ethnic heritage have higher selfesteem, a better self-image, and a stronger
sense of personal identity (Roberts et al., 1999;
Tse, 1999). They are also less likely to engage
in drug use (Marsiglia et al., 2004) or violent
behavior (French, Kim, & Pillado, 2006).
Group pride, positive models, and a more
tolerant society could do much to keep a broad
range of options open to all adolescents.
Ideally, this change can encourage greater maturity and independence. However, if the search for identity ends too soon, it may
leave Samantha with a distorted, poorly formed sense of self
( Figure 3.19).
•
The Search for Identity
Identity formation is a key task of adolescence (Schwartz,
2008). Of course, problems of identity occur at other times too.
But in a very real sense, puberty signals that it’s time to begin
forming a new, more mature self-image (Douvan, 1997). Many
problems stem from unclear standards about the role adolescents should play within society. Are they adults or children?
Should they be autonomous or dependent? Should they work
or play? Such ambiguities make it difficult for young people
to form clear images of themselves and of how they should act
(Alsaker, 1995).
Answering the question “Who am I?” is also spurred by cognitive development. After adolescents have attained the stage of
formal operations, they are better able to ask questions about their
place in the world and about morals, values, politics, and social
relationships. Then too, being able to think about hypothetical
possibilities allows the adolescent to contemplate the future and
ask more realistically, “Who will I be?” (Côté, 2006b). (See “Ethnic Diversity and Identity.”)
Figure 3.19 Dramatic differences in physical size and maturity are found in
•adolescents
of the same age. The girls pictured are all 13, the boys 16. Maturation
Adolescence The culturally defined period between childhood and
adulthood.
that occurs earlier or later than average can affect the “search for identity.” (Reprinted
Puberty The biologically defined period during which a person matures
sexually and becomes capable of reproduction.
with permission of Nelson Prentiss.)
104
CHAPTER 3
C R IT ICAL T H I N KI N G
The Twixters
As you read this text, we encourage you to
reflect on new ideas and concepts by thinking critically about them. Consider, for example, the term adulthood. Is becoming an adult
strictly a biological event? Meet 22-year-old
Kirsten:
Kirsten is a “twixter”: twentysomething,
still living at home, not yet married, with no
children, and no settled career. In England,
twixsters are called “kippers” (Kids In Parents’
Pockets Eroding Retirement Savings). In
Australia they are “boomerang kids” (they
always come back home). And in Germany
they are “Nesthocker” (nest squatters). Are
twixters adolescents who are taking longer to
find their identity? Or are they young adults
avoiding their need to enter the adult world?
Are they self-indulgent individuals trapped in
a “maturity gap” (Galambos, Barker, & TiltonWeaver, 2003)? Or are they part of a new
social status that could be called “emerging
adulthood” (Arnett & Tanner, 2006)?
According to psychologist Jeffrey Arnett,
emerging adulthood is increasingly common in affluent Westernized cultures that
allow young people to take longer to settle
into their adult roles (Arnett, 2000, 2004).
However, in less affluent countries, as in
poorer parts of America, most adolescents continue to “become adults” at much
younger ages (Arnett & Galambos, 2003).
Thus, words like adolescent or adulthood cannot be defined solely in terms of physical
maturation. Sociocultural factors also play a
role in defining when we stop being children
or become adults (Arnett, 2004).
© Zits Partnership. Reprinted with special permission of King
Features Syndicate.
“When our mothers were our age, they were
engaged. . . . They at least had some idea what
they were going to do with their lives. . . . I,
on the other hand, will have a dual degree in
majors that are ambiguous at best and impractical at worst (English and political science), no
ring on my finger and no idea who I am, much
less what I want to do. . . . I realize that having
nothing ahead to count on means I now have
to count on myself; that having no direction
means forging one of my own.” (Page, 1999).
The Transition to Adulthood
Today the challenge of identity formation is further complicated
by the fact that more and more young people are deferring young
adulthood, preferring to prolong identity explorations into their
20s before they commit to long-term choices in love and work
(Arnett, 2000, 2004; Arnett & Tanner, 2006). According to
sociologist James Côté, Western industrialized societies, like the
United States and Canada, are becoming increasingly tolerant
of this period of extended adolescence (Côté, 2006a). (See “The
Twixters.”)
Samantha may live with Olivia and Tom until her mid-20s,
delaying her transition to adulthood. Alternately, she may make
the transition to young adulthood during the traditional 18-to-21
period. Regardless, she will eventually face the primary adult issues
of marriage, children, and career. How she manages, especially in
her core relationships, will determine whether she feels a sense of
intimacy or feels isolated from others.
In many ways adolescence and young adulthood are more emotionally turbulent than midlife or old age. One important aspect
of the emotional turbulence of adolescence and young adulthood
is the struggle with right and wrong — in other words, the need to
develop moral values.
Moral Development —
Growing a Conscience
Gateway Question: How do we develop morals and values?
A person with a terminal illness is in great pain. She is pleading for
death. Should extraordinary medical efforts be made to keep her
alive? A friend of yours desperately needs to pass a test and asks
you to help him cheat. Will you do it? These are moral questions,
or questions of conscience.
Human Development
Moral development starts in childhood and continues into
adulthood (Turiel, 2006). Through this process, we acquire values, beliefs, and thinking patterns that guide responsible behavior. Moral values are especially likely to come into sharper focus
during adolescence and the transition to adulthood, as capacities
for self-control and abstract thinking increase (Hart & Carlo,
2005). Let’s take a brief look at this interesting aspect of personal
development.
Levels of Moral Development
How are moral values acquired? In an influential account, psychologist Lawrence Kohlberg (1981) held that we learn moral
values through thinking and reasoning. To study moral development, Kohlberg posed dilemmas to children of different ages. The
following is one of the moral dilemmas he used (Kohlberg, 1969,
adapted).
A woman was near death from cancer, and there was only one drug that
might save her. It was discovered by a druggist who was charging 10 times
what it cost to make the drug. The sick woman’s husband could only pay
$1,000, but the druggist wanted $2,000. He asked the druggist to sell it
cheaper or to let him pay later. The druggist said no. So the husband became
desperate and broke into the store to steal the drug for his wife. Should he
have done that? Was it wrong or right? Why?
Each child was asked what action the husband should take.
Kohlberg classified the reasons given for each choice and identified three levels of moral development. Each is based not so much
on the choices made, but on the reasoning used to arrive at a
choice.
At the lowest, preconventional level, moral thinking is guided
by the consequences of actions (punishment, reward, or an
exchange of favors). For example, a person at this level might reason that “The man shouldn’t steal the drug because he could get
caught and sent to jail” (avoiding punishment) or “It won’t do him
any good to steal the drug because his wife will probably die before
he gets out of jail” (self-interest).
At the second, or conventional level, reasoning is based on a
desire to please others or to follow accepted authority, rules, and
values. For example, a person at this intermediate level might say
“He shouldn’t steal the drug because others will think he is a thief.
His wife would not want to be saved by thievery” (avoiding disapproval) or “Although his wife needs the drug, he should not break
the law to get it. Everyone has to obey the law. His wife’s condition
does not justify stealing” (traditional morality of authority).
At the highest, or postconventional level, moral behavior is
directed by self-chosen ethical principles that tend to be general, comprehensive, or universal. People at this level place high
value on justice, dignity, and equality. For example, a highly
principled person might say “He should steal the drug and then
inform the authorities that he has done so. He will have to face
a penalty, but he will have saved a human life” (self-chosen ethical principles).
Does everyone eventually reach the highest level? People advance
at different rates, and many fail to reach the postconventional level
105
of moral reasoning. In fact, many do not even reach the conventional level. For instance, one English survey revealed that
11 percent of men and 3 percent of women would commit murder
for $1 million if they could be sure of getting away with the crime
(“They’d kill,” 1991).
The preconventional level is most characteristic of young children and delinquents (Forney, Forney, & Crutsinger, 2005). Conventional, group-oriented morals are typical of older children and
most adults. Kohlberg estimated that only about 20 percent of the
adult population achieves postconventional morality, representing
self-direction and higher principles. (It would appear that few of
these people enter politics!)
Developing a “moral compass” is an important part of growing
up. Many of the choices we make every day involve fundamental
questions of right and wrong. Being able to think clearly about
such questions is essential to becoming a responsible adult.
Justice or Caring?
Carol Gilligan (1982) pointed out that Kohlberg’s system is concerned mainly with justice. Based on studies of women who faced
real-life dilemmas, Gilligan argued that there is also an ethic of
caring about others. As one illustration, Gilligan presented the
following story to 11- to 15-year-old American children.
The Porcupine and the Moles
Seeking refuge from the cold, a porcupine asked to share a cave for the
winter with a family of moles. The moles agreed. But because the cave
was small, they soon found they were being scratched each time the porcupine moved about. Finally, they asked the porcupine to leave. But the
porcupine refused, saying, “If you moles are not satisfied, I suggest that
you leave.”
Boys who read this story tended to opt for justice in resolving
the dilemma: “It’s the moles’ house. It’s a deal. The porcupine
leaves.” In contrast, girls tended to look for solutions that would
keep all parties happy and comfortable, such as “Cover the porcupine with a blanket.”
Gilligan’s point is that male psychologists have, for the most
part, defined moral maturity in terms of justice and autonomy.
From this perspective, a woman’s concern with relationships can
look like a weakness rather than a strength. (A woman who is concerned about what pleases or helps others would be placed at the
conventional level in Kohlberg’s system.) But Gilligan believes
that caring is also a major element of moral development, and she
Moral development The development of values, beliefs, and thinking
abilities that act as a guide regarding what is acceptable behavior.
Preconventional moral reasoning Moral thinking based on the
consequences of one’s choices or actions (punishment, reward, or an
exchange of favors).
Conventional moral reasoning Moral thinking based on a desire to
please others or to follow accepted rules and values.
Postconventional moral reasoning Moral thinking based on carefully
examined and self-chosen moral principles.
106
CHAPTER 3
suggests that males may lag in achieving it (Botes, 2000; Gilligan
& Attanucci, 1988).
Does the evidence support Gilligan’s position? Several studies
have found little or no difference in men’s and women’s overall
moral reasoning abilities (Glover, 2001; Wilson, 1995). Indeed,
both men and women may use caring and justice to make moral
decisions. The moral yardstick they use appears to depend on
the situation they face (Wark & Krebs, 1996). Just the same,
Gilligan deserves credit for identifying a second major way in
which moral choices are made. It can be argued that our best
moral choices combine justice and caring, reason and emotion — which may be what we mean by wisdom (Pasupathi &
Staudinger, 2001).
The Story of a Lifetime —
Rocky Road or Garden Path?
K NOW LED G E B U I L D E R
Gateway Question: What are the typical tasks and dilemmas
through the life span?
Erik Erikson’s psychosocial theory provides a good overview of the
major psychological conflicts that occur during a “typical” life. In
later adulthood we all face many additional challenges, including
physical aging. Regardless, it is possible to age successfully. We also
must face our own mortality and inevitable death.
Every life is marked by a number of developmental milestones.
These are notable events, markers, or turning points in personal
development. Some examples include graduating from school,
voting for the first time, getting married, watching a child leave
home (or move back!), the death of a parent, becoming a grandparent, retirement, and one’s own death. Thus far, we have traced
Samantha’s progress through childhood, adolescence, and young
adulthood. What challenges lie ahead for her?
Adolescence, Young Adulthood,
and Moral Development
Erikson’s Psychosocial Theory
RECITE
1. In North America the primary criterion for the transition from adolescence to adulthood is marriage. T or F?
2. Identify formation is spurred by ________________ and
________________ ________________.
3. According to Jeffrey Arnett, the trend in affluent Westernized cultures toward allowing young people to take longer to settle into
their adult roles is best referred to as
a. emerging adulthood
b. hurried childhood
c. a maturity gap
d. extended adolescence
4. According to Kohlberg, the conventional level of moral development
is marked by a reliance on outside authority. T or F?
5. Self-interest and avoiding punishment are elements of postconventional morality. T or F?
6. About 80 percent of all adults function at the postconventional level
of moral reasoning. T or F?
7. Gilligan regards gaining a sense of justice as the principal basis of
moral development. T or F?
REFLECT
Critical Thinking
8. Are labels like “adolescent” or “young adult” reflective of heredity or
environment?
Relate
To what extent does the concept of identity formation apply to your own
experience during adolescence?
Do you know any twixters? (Are you one?) Do you think twixters are
adolescents taking longer to find their identity or young adults avoiding
their need to establish themselves in the world of adults?
At what stage of moral development do you think most terrorists
function?
Perhaps the best way to get a preview of Samantha’s life is to
consider some of the major psychological challenges she is likely
to encounter. Broad similarities can be found in the life stages of
infancy, childhood, adolescence, young adulthood, middle adulthood, and old age. Each stage confronts a person with new developmental tasks that must be mastered for optimal development.
Examples are learning to read in childhood, adjusting to sexual
maturity in adolescence, and establishing a vocation as an adult.
In an influential book titled Childhood and Society (1963), personality theorist Erik Erikson (1903–1994) suggests that we face
a specific psychosocial dilemma, or “crisis,” at each stage of life. A
psychosocial dilemma is a conflict between personal impulses
and the social world. Resolving each dilemma creates a new balance between a person and society. A string of “successes” produces healthy development and a satisfying life. Unfavorable outcomes throw us off balance, making it harder to deal with later
crises. Life becomes a “rocky road,” and personal growth is stunted.
Table 3.3 lists Erikson’s dilemmas.
•
Table 3.3
• Erikson’s Psychosocial Dilemmas
Age
Characteristic Dilemma
Birth to 1 year
Trust versus mistrust
1 to 3 years
Autonomy versus shame and doubt
3 to 5 years
Initiative versus guilt
6 to 12 years
Industry versus inferiority
Adolescence
Identity versus role confusion
Young adulthood
Intimacy versus isolation
Middle adulthood
Generativity versus stagnation
Late adulthood
Integrity versus despair
Answers: 1. F 2. puberty, cognitive development 3. a 4. T 5. F 6. F 7. F
8. Environment, rather than heredity, is the better answer. Even better,
the meanings of terms like “adolescence” or “adult” vary considerably
from culture to culture, indicating that it is really a matter of definition
(Côté, 2006a).
Human Development
107
dom to play, ask questions, use imagination, and choose activities.
Feelings of guilt about initiating activities are formed if parents
criticize severely, prevent play, or discourage a child’s questions.
Sarah Putnum/Index Stock Imagery/Photolibrary
Stage Four, 6–12 Years: Industry versus Inferiority
Personality theorist Erik Erikson (1903–1994) is best known for his life-stage
theory of human development.
What are the major developmental tasks and life crises? A brief
description of each psychosocial dilemma follows.
Stage One, First Year of Life: Trust versus Mistrust
During the first year of life, children are completely dependent on
others. Erikson believes that a basic attitude of trust or mistrust
is formed at this time. Trust is established when babies are given
warmth, touching, love, and physical care. Mistrust is caused by
inadequate or unpredictable care and by parents who are cold,
indifferent, or rejecting. Basic mistrust may later cause insecurity,
suspiciousness, or an inability to relate to others. Notice that trust
comes from the same conditions that help babies become securely
attached to their parents.
Stage Two, 1–3 Years: Autonomy
versus Shame and Doubt
In stage two, children express their growing self-control by climbing, touching, exploring, and trying to do things for themselves.
Tom and Olivia fostered Samantha’s sense of autonomy by
encouraging her to try new skills. However, her first efforts were
sometimes crude, involving spilling, falling, wetting, and other
“accidents.” If Tom and Olivia had ridiculed or overprotected
Samantha, they might have caused her to feel shameful about her
actions and doubt her abilities.
Stage Three, 3–5 Years: Initiative versus Guilt
In stage three, children move beyond simple self-control and begin
to take initiative. Through play, children learn to make plans and
carry out tasks. Parents reinforce initiative by giving children free-
Many events of middle childhood are symbolized by that fateful day when you first entered school. With dizzying speed your
world expanded beyond your family, and you faced a whole series
of new challenges.
The elementary school years are a child’s “entrance into life.” In
school, children begin to learn skills valued by society, and success
or failure can affect a child’s feelings of adequacy. Children learn a
sense of industry if they win praise for productive activities, such
as building, painting, cooking, reading, and studying. If a child’s
efforts are regarded as messy, childish, or inadequate, feelings of
inferiority result. For the first time, teachers, classmates, and
adults outside the home become as important as parents in shaping attitudes toward oneself.
Stage Five, Adolescence: Identity versus Role Confusion
As we have noted, adolescence is often a turbulent time. Erikson
considers a need to answer the question “Who am I?” the primary
task during this stage of life. As Samantha matures mentally and
physically, she will have new feelings, a new body, and new attitudes. Like other adolescents, she will need to build a consistent
identity out of her talents, values, life history, relationships, and
the demands of her culture (Côté & Levine, 2002). Her conflicting
experiences as a student, friend, athlete, worker, daughter, lover,
and so forth must be integrated into a unified sense of self. Persons
who fail to develop a sense of identity suffer from role confusion,
an uncertainty about who they are and where they are going.
Stage Six, Young Adulthood: Intimacy versus Isolation
What does Erikson believe is the major conflict in early adulthood?
In stage six, the individual feels a need for intimacy in his or her
life. After establishing a stable identity, a person is prepared to
Developmental task Any skill that must be mastered, or personal
change that must take place, for optimal development.
Psychosocial dilemma A conflict between personal impulses and the
social world.
Trust versus mistrust A conflict early in life about learning to trust
others and the world.
Autonomy versus shame and doubt A conflict created when growing
self-control (autonomy) is pitted against feelings of shame and doubt.
Initiative versus guilt A conflict between learning to take initiative
and overcoming feelings of guilt about doing so.
Industry versus inferiority A conflict in middle childhood centered
around lack of support for industrious behavior, which can result in
feelings of inferiority.
Identity versus role confusion A conflict of adolescence, involving
the need to establish a personal identity.
108
CHAPTER 3
share meaningful love or deep friendship with others. By intimacy, Erikson means an ability to care about others and to share
experiences with them. In line with Erikson’s view, 75 percent of
college-age men and women rank a good marriage and family
life as important adult goals (Bachman & Johnson, 1979). And
yet, marriage or sexual involvement is no guarantee of intimacy:
Many adult relationships remain shallow and unfulfilling. Failure
to establish intimacy with others leads to a deep sense of isolation
(feeling alone and uncared for in life). This often sets the stage for
later difficulties.
a sense of integrity (self-respect). This allows them to face aging
and death with dignity. If previous life events are viewed with
regret, the elderly person experiences despair (heartache and
remorse). In this case, life seems like a series of missed opportunities. The person feels like a failure and knows it’s too late to reverse
what has been done. Aging and the threat of death then become
sources of fear and depression.
The Life Span in Perspective
To squeeze a lifetime into a few pages, we had to ignore countless
details. Although much is lost, the result is a clearer picture of an
entire life cycle. Is Erikson’s description, then, an exact map of
Samantha’s past and her future — or your own? Probably not. Still,
psychosocial dilemmas are major events in many lives. Knowing
about them may allow you to anticipate typical trouble spots in
your own life. You may also be better prepared to understand the
problems and feelings of friends and relatives at various points in
the life cycle.
Stage Seven, Middle Adulthood:
Generativity versus Stagnation
According to Erikson, an interest in guiding the next generation
provides emotional balance in mature adulthood. Erikson called
this quality generativity. It is expressed by caring about oneself, one’s children, and future generations. Generativity may be
achieved by guiding one’s own children or by helping other children (as a teacher or coach, for example). Productive or creative
work can also express generativity. In any case, a person’s concerns
and energies must broaden to include the welfare of others and
society as a whole. Failure to do this is marked by a stagnant concern with one’s own needs and comforts. Life loses meaning, and
the person feels bitter, dreary, and trapped (Friedman, 2004).
Later Adulthood: Will You Still
Need Me When I’m 64?
Gateway Question: What is involved in well-being during later
adulthood?
Although Erikson’s dilemmas extend into adulthood, they are not
the only challenges adults face. Others are all too familiar: marital
strife, divorce, career difficulties, unemployment, health problems,
financial pressures, legal conflicts, and personal tragedies — to
name but a few. How do people maintain a state of well-being
as they run the gauntlet of modern life? Psychologist Carol Ryff
(1995; Ryff, Singer, & Palmersheim, 2004) believes that wellbeing during adulthood has six elements:
Stage Eight, Late Adulthood: Integrity versus Despair
What does Erikson see as the conflicts of old age? Old age is a time
of reflection. According to Erikson, when Samantha grows old
she must be able to look back over her life with acceptance and
satisfaction. People who have lived richly and responsibly develop
Jeff Greenberg/PhotoEdit
1.
2.
3.
4.
5.
6.
According to Erikson, an interest in future generations characterizes optimal
adult development.
Self-acceptance
Positive relations with others
Autonomy (personal freedom)
Environmental mastery
A purpose in life
Continued personal growth
Ryff found that for many older adults, age-related declines are
offset by positive relationships and greater mastery of life’s demands
(Ryff & Keyes, 1995). Thus, sharing life’s joys and sorrows with
others, coupled with a better understanding of how the world
works, can help carry people through midlife and into their later
years (Ryff & Singer, 2000; Ryff, Singer, & Palmersheim, 2004).
Despite the emphasis on youth in our culture, middle age and
beyond can be a rich period of life in which people feel secure,
happy, and self-confident (Rubenstein, 2002).
A Midlife Crisis?
But don’t people face a “midlife crisis” at this point in their lives? Yes
and no. Serious difficulties at the midpoint of life are certainly not
universal. Most people thrive during middle adulthood and have
Human Development
no special problems. Only about a quarter of men and women
believe they have experienced a midlife crisis (Wethington, Kessler, & Pixley, 2004).
Nevertheless, midlife does pose special challenges. According
to Roger Gould (1975), a psychiatrist interested in adult personality, North American adults actually experience two “crisis” points
in their development.
Crisis of Questions
According to Gould, around the age of 30 many people experience
a minor life crisis. The heart of this crisis is a serious questioning
of what life is all about. People tend to ask themselves, “Is this
it?” and confidence in previous choices and values can waver.
Unsettled by these developments, the person actively searches for
a style of living that will bring more meaning to life. Marriages are
particularly vulnerable during this time of dissatisfaction. Extramarital affairs and divorces are common symptoms of the “crisis
of questions.”
Crisis of Urgency
People in their late 30s and 40s are typically beginning to become
more aware of the reality of death. Having a limited number of
years to live begins to exert pressure on the individual. Intensified
attempts are made to succeed at a career or to achieve one’s life
goals. Generativity, in the form of nurturing, teaching, or serving
others, helps alleviate many of the anxieties of this stage.
If a midlife crisis does occur, what does it look like? Psychologist
Daniel Levinson carried out a classic in-depth study of adulthood
and identified several periods when people typically make major
transitions. A transition period ends one life pattern and opens
the door to new possibilities (Levinson, 1986). At such times,
people address concerns about their identity, their work, and relationships to others.
Levinson’s first study focused on men. As they approached the
midlife transition (between the ages of 37 and 41), most men went
through a period of instability, anxiety, and change. (Notice that
this corresponds closely to Gould’s crisis-of-urgency period.) In a
later study, Levinson found that most of what he learned about
men also applies to women (Levinson & Levinson, 1996).
Of the men Levinson studied, roughly half defined the midlife
period as a “last chance” to achieve their goals. Such goals were
often stated as a key event, such as reaching a certain income or
becoming a supervisor, a full professor, a shop steward, and so
forth. For these men the midlife period was stressful but manageable.
A smaller percentage of men experienced a serious midlife
decline. Many of these men had to face the fact that they had chosen a dead-end job or lifestyle. Others had achieved financial success but felt that what they were doing was pointless.
In a third pattern, a few hardy individuals appeared to “break
out” of a seriously flawed life structure. For them, a decision to
“start over” was typically followed by 8 to 10 years of rebuilding.
In what ways does the midlife transition differ for women? Compared with men, women were less likely to enter adulthood with
specific “goals.” As a result, they were less likely to define “success”
109
in terms of some key event. Rather than focusing on external goals,
women tended to seek changes in personal identity at midlife. For
example, a woman might become more self-reliant and independent — qualities she might have regarded as “masculine” earlier in
life (Levinson & Levinson, 1996). But make no mistake, midlife
can be challenging for women, too (Wethington, 2000). In another
survey of middle-aged women, two thirds said they made major
changes in their lives between ages 37 and 43 (Stewart & Vandewater, 1999).
Midcourse Corrections
In summary, people tend to move through cycles of stability and
transition in their adult lives (Ornstein & Isabella, 1990). However, it is more common to make a “midcourse correction,” at
midlife than it is to survive a “crisis” (Lachman, 2004). Ideally, the
midlife transition involves reworking old identities, achieving valued goals, finding one’s own truths, and preparing for old age. Taking stock may be especially valuable at midlife, but reviewing past
choices to prepare for the future is helpful at any age (Lewchanin
& Zubrod, 2001). For some people, difficult turning points in life
can serve as “wake-up calls” that create opportunities for personal
growth (Wethington, 2003).
Old Age
After the late 50s, personal development is complicated by physical aging. However, it is wrong to believe that most elderly people
are sickly, infirm, or senile. (Nowadays, 60 is the new 40, an idea
both of your authors whole-heartedly agree with!) Only about
5 percent of those older than 65 are in nursing homes. Mentally,
many elderly persons are at least as capable as the average young
adult. On intellectual tests, top scorers over the age of 65 match
the average for men younger than 35. What sets these silver-haired
stars apart? Typically they are people who have continued to work
and remain intellectually active (Salthouse, 2004). Gerontologist
Warner Schaie (1994, 2005) found that you are most likely to stay
mentally sharp in old age if:
1. You remain healthy.
2. You live in a favorable environment. (You are educated and
have a stimulating occupation, an above-average income, and
an intact family.)
3. You are involved in intellectually stimulating activities (reading, travel, cultural events, continuing education, clubs, professional associations).
Intimacy versus isolation The challenge of overcoming a sense of
isolation by establishing intimacy with others.
Generativity versus stagnation A conflict of middle adulthood
in which self-interest is countered by an interest in guiding the next
generation.
Integrity versus despair A conflict in old age between feelings of
integrity and the despair of viewing previous life events with regret.
Transition period Time span during which a person leaves an existing
life pattern behind and moves into a new pattern.
110
CHAPTER 3
Tony Ranze/AFP/Getty Images
At age 77,
John Glenn
became the
oldest person
to fly into
space, in
October 1998.
Glenn was
also the first
American astronaut
to orbit Earth, in 1962.
As Glenn’s space adventure shows,
aging does not inevitably bring
an end to engaging in
challenging activities.
4.
5.
6.
7.
You have a flexible personality.
You are married to a smart spouse.
You maintain your perceptual processing speed.
You were satisfied with your accomplishments in midlife.
A shorter summary of this list is “Those who live by their wit
die with their wits.”
Successful Aging
What are the keys to successful aging? They are not unlike the elements of well-being at midlife. Four psychological characteristics
shared by the healthiest, happiest older people are (de Leon, 2005;
Vaillant, 2002):
Optimism, hope, and an interest in the future
Gratitude and forgiveness; an ability to focus on what is good
in life
Empathy; an ability to share the feelings of others and see the
world through their eyes
Connection with others; an ability to reach out, to give and
receive social support
Ageism is often expressed through patronizing language. Older
people are frequently spoken to in an overly polite, slow, loud, and
simple way implying that they are infirm, even when they are not
(Nelson, 2005). Popular stereotypes of the “dirty old man,” “meddling old woman,” “senile old fool,” and the like also help perpetuate myths about aging. But such stereotypes are clearly wrong: A
tremendous diversity exists among the elderly — ranging from the
infirm to aerobic-dancing grandmothers.
In many occupations, older workers perform well in jobs that
require both speed and skill. Of course, people do experience a
gradual loss of fluid abilities (those requiring speed or rapid learning) as they age but often this can be offset by many crystallized
abilities (learned knowledge and skills), such as vocabulary and
stored-up facts, which may actually improve — at least into the 60s
(Schaie, 2005). Overall, very little loss of job performance occurs
as workers grow older. In the professions, wisdom and expertise
can usually more than compensate for any loss of mental quickness
(Ericsson, 2000). Basing retirement solely on a person’s age makes
little sense.
Death and Dying — The Final Challenge
Gateway Question: How do people typically react to death?
DEAR ABBY: Do you think about dying much? (signed) CURIOUS
DEAR CURIOUS: No, it’s the last thing I want to do.
“I’m not afraid of dying. I just don’t want to be there when it happens.”
Woody Allen
“Why not? Why not?” LSD guru Timothy Leary (his last words before dying)
The statistics on death are very convincing: Everyone dies. In
spite of this, most of us are poorly informed about a process that is
as basic as birth. We have seen throughout this chapter that it is
valuable to understand major trends in the course of development.
With this in mind, let us now explore emotional responses to
death, the inevitable conclusion of every life.
Aging and Ageism
You have almost certainly encountered ageism in one way or
another. Ageism, which refers to discrimination or prejudice
based on age, can oppress the young as well as the old. For
instance, a person applying for a job may just as well be told
“You’re too young” as “You’re too old.” In some societies ageism
is expressed as respect for the elderly. In Japan, for instance, aging
is seen as positive, and greater age brings more status and respect.
In most Western nations, however, ageism tends to have a negative
impact on older individuals (Ng, 2002).
© Michael Newman/PhotoEdit
Actually, these are excellent guidelines for well-being at any stage
of adulthood.
In summary, enlightened views of aging call for an end to the
forced obsolescence of the elderly. As a group, older people represent a valuable source of skill, knowledge, and energy that we can’t
afford to cast aside. As we face the challenges of this planet’s uncertain future, we need all the help we can get!
Death may be inevitable, but it can be faced with dignity and sometimes even
humor. Mel Blanc’s famous sign-off, “That’s all folks,” is engraved on a marble
headstone over his grave. Blanc was the voice of Bugs Bunny, Porky Pig, and
many other cartoon characters.
Human Development
111
It might seem that as people grow older they would fear death
more. However, older persons actually have fewer death fears than
younger people. Older people more often fear the circumstances of
dying, such as pain or helplessness, rather than death itself (Thorson & Powell, 1990). These findings seem to show a general lack
of death fears, but they may actually reflect a widespread denial of
death. Notice how denial is apparent in the language used to talk
about death: Often we speak of a dead person as having “passed
away,” “expired,” “gone to God,” or “breathed one’s last.”
Many people have little direct experience with death until they,
themselves, are fairly old. The average person’s exposure to death
consists of the artificial and unrealistic portrayals of death on TV.
By the time the average person is 17 years old, she or he will have
witnessed thousands of TV deaths. With few exceptions these are
homicides, not deaths due to illness or aging.
Not all terminally ill persons display all these reactions, nor
do they always occur in this order. Individual styles of dying
vary greatly. Generally, there does tend to be a movement from
initial shock, denial, and anger toward eventual acceptance.
However, some people who seem to have accepted death may
die angry and raging against the inevitable. Conversely, the
angry fighter may let go of the struggle and die peacefully. In
general, one’s approach to dying will mirror his or her style of
living (Yedidia & MacGregor, 2001).
It is a mistake, then, to think that Kübler-Ross’s list is a series of
stages to go through in order or that there is something wrong if a
person does not show all these emotions. Rather, the list describes
typical reactions to impending death. Note, as well, that many of
the same reactions accompany any major loss, be it divorce, loss of
a home due to fire, death of a pet, or loss of a job.
Reactions to Impending Death
Implications
A direct and highly influential account of emotional responses
to death comes from the work of Elisabeth Kübler-Ross (1926–
2004). Kübler-Ross was a thanatologist (THAN-ah-TOL-oh-jist:
one who studies death). Over the years she spent hundreds of hours
at the bedsides of the terminally ill, where she observed five basic
emotional reactions to impending death (Kübler-Ross, 1975).
1. Denial and isolation. A typical first reaction is to deny
death’s reality and isolate oneself from information confirming that death is really going to occur. Initially the person
may be sure that “It’s all a mistake.” “Surely,” she or he thinks,
“the lab reports have been mixed up or the doctor made an
error.” This sort of denial may proceed to attempts to avoid
any reminder of the situation.
2. Anger. Many dying individuals feel anger and ask, “Why
me?” As they face the ultimate threat of having life torn away,
their anger may spill over into rage toward the living. Even
good friends may temporarily evoke anger because their
health is envied.
3. Bargaining. In another common reaction, the terminally
ill bargain with themselves or with God. The dying person
thinks, “Just let me live a little longer and I’ll do anything
to earn it.” Individuals may bargain for time by trying to be
“good” (“I’ll never smoke again”), by righting past wrongs, or
by praying that if they are granted more time they will dedicate themselves to their religion.
4. Depression. As death draws near and the person begins to recognize that it cannot be prevented, feelings of futility, exhaustion, and deep depression may set in. The person realizes she
or he will be separated from friends, loved ones, and the familiar routines of life, and this causes a profound sadness.
5. Acceptance. If death is not sudden, many people manage to
come to terms with dying and accept it calmly. The person
who accepts death is neither happy nor sad, but at peace with
the inevitable. Acceptance usually signals that the struggle
with death has been resolved. The need to talk about death
ends, and silent companionship from others is frequently all
the person desires.
How can I make use of this information? First, it can help both
the dying and survivors to recognize and cope with periods of
depression, anger, denial, and bargaining. Second, it helps to
realize that close friends or relatives may feel many of the same
emotions before or after a person’s death because they, too, are
facing a loss.
Perhaps the most important thing to recognize is that the
dying person needs to share feelings with others and to discuss
death openly. Too often, dying persons feel isolated and separated
from others. Adults tend to “freeze up” with someone who is
dying. For such people, thanatologist Kirsti Dyer (2001) has this
advice:
•
•
•
•
•
•
•
Be yourself and relate person to person.
Be ready to listen again and again.
Be respectful.
Be aware of feelings and nonverbal cues.
Be comfortable with silence.
Be genuine.
Most of all, be there.
Understanding what the dying person is going through may
make it easier for you to offer support at this important time. A
simple willingness to be with the person and to honestly share his
or her feelings can help bring dignity, acceptance, and meaning to
death (Holstein, 1997). Today, many terminally ill individuals also
benefit from hospice care, which can improve the quality of life in
a person’s final days. Hospices typically offer support, guidance,
pain relief, and companionship. In short, the dying person is made
comfortable and feels loved and respected (Lynn, 2001). As each
of us faces the end of life, to die well may be no less an accomplishment than to live well.
Ageism Discrimination or prejudice based on a person’s age.
Thanatologist A specialist who studies emotional and behavioral
reactions to death and dying.
CHAPTER 3
K NOW LED G E B U I L D E R
Challenges Across the Lifespan
RECITE
As a way to improve your memory, you might find it helpful to summarize
Erikson’s eight life stages. Complete this do-it-yourself summary and compare your answers to those given below.
———————————————————————————————————
Stage
Crisis
Favorable Outcome
———————————————————————————————————
First year of life
1. ______________ vs.
Faith in the environ2. ______________
ment and in others
———————————————————————————————————
Ages 1–3
Autonomy vs.
Feelings of self3. ______________
control and adequacy
———————————————————————————————————
Ages 3–5
4. ______________ vs.
Ability to begin one’s
guilt
own activities
———————————————————————————————————
Ages 6–12
Industry vs.
Confidence in
5. ______________
productive skills,
learning how to work
———————————————————————————————————
Adolescence
6. ______________ vs.
An integrated image
role confusion
of oneself as a unique
person
———————————————————————————————————
Young adulthood
Intimacy vs.
Ability to form bonds
7. ______________
of love and friendship
with others
———————————————————————————————————
Middle adulthood
Generativity vs.
8. ______________
Concern for family,
society, and future
generations
———————————————————————————————————
Late adulthood
9. ______________ vs.
Sense of dignity and
10. __________________ fulfillment, willingness to face death
11. Nearly everyone experiences a midlife crisis sometime around age
40. T or F?
12. After age 65, a large proportion of older people show significant
signs of mental disability and most require special care. T or F?
13. Job performance tends to decline rapidly in older workers. T or F?
14. In the reaction that Kübler-Ross describes as bargaining, the dying
individual asks, “Why me?” T or F?
REFLECT
Critical Thinking
15. Trying to make generalizations about development throughout life
is complicated by at least one major factor. What do you think it is?
Relate
See if you can think of a person you know who is facing one of Erikson’s
psychosocial dilemmas. Now see if you can think of specific people who
seem to be coping with each of the other dilemmas.
See if you can describe three instances of ageism you have witnessed.
Answers: 1. Trust 2. mistrust 3. shame or doubt 4. Initiative 5. inferiority 6. Identity 7. isolation 8. stagnation 9. Integrity 10. despair 11. F
12. F 13. F 14. F 15. Different cohorts (groups of people born in the
same year) live in different historical times. People born in various
decades may have very different life experiences. This makes it difficult
to identify universal patterns (Stewart & Ostrove, 1998).
112
PSY C HO L O GY IN A CT ION
Effective Parenting — Raising Healthy Children
And yet, it is not easy to have a positive interaction while disciplining your child. This
is one reason why overly permissive parents
avoid disciplining their children.
Effective discipline is created through communication that is fair but loving, authoritative yet sensitive. It socializes a child without
destroying the bond of love and trust between
parent and child. Children should feel free to
express their deepest feelings. However, this
does not mean they can do whatever they
please. Rather, the child is allowed to move
freely within consistent, well-defined boundaries for acceptable behavior.
Effective Discipline
Image 100/SuperStock
Gateway Question: How do effective parents
discipline and communicate with their
children?
Authoritative parents help their children grow
up with a capacity for love, joy, fulfillment,
responsibility, and self-control through positive parent-child interactions. Positive interactions occur when parents spend enjoyable
time encouraging their children in a loving
and mutually respectful fashion (Dinkmeyer,
McKay, & Dinkmeyer, 1997).
As any parent can tell you, it is all well and
good to talk about positive interactions until
little Johnny misbehaves (and he will, count
on it!). As children mature and become more
independent, parents must find ways to control their children’s behavior. (“No, you may
not smear banana pudding on daddy’s face.”)
When parents fail to provide discipline (guidance regarding acceptable behavior), children
become antisocial, aggressive, and insecure.
Parents typically discipline children in one of
three ways. Power assertion refers to physical
punishment or a show of force, such as taking
away toys or privileges. As an alternative, some
parents use withdrawal of love (withholding
affection) by refusing to speak to a child, threatening to leave, rejecting the child, or otherwise
acting as if the child is temporarily unlovable.
Management techniques combine praise, recognition, approval, rules, reasoning, and the
like to encourage desirable behavior. Each of
these approaches can control a child’s behavior,
but their side effects differ considerably.
What are the side effects? Power-oriented
techniques — particularly harsh or severe
113
Calvin and Hobbes © Watterson. Reprinted with permission of
Universal Press Syndicate. All rights reserved.
Human Development
Calvin
and
Hobbes
physical punishment — are associated with
fear, hatred of parents, and a lack of spontaneity and warmth. Most children show no
signs of long-term damage from spanking — if
spanking is backed up by supportive parenting (Baumrind, Larzelere, & Cowan, 2002).
However, emotional damage does occur if
spankings are severe, frequent, or coupled with
harsh parenting. In addition, frequent spanking tends to increase aggression, and it leads to
more problem behaviors, not fewer (McLoyd
& Smith, 2002). After reviewing many studies, psychologist Elizabeth Gershoff concludes that parents should minimize spanking
or avoid it entirely (Gershoff, 2002).
bridges
Punishment also has important effects
on learning. For more tips on how
to use punishment wisely, see
Chapter 7, pages 240–241.
Withdrawal of love produces children who
tend to be self-disciplined. You could say that
such children have developed a good conscience. Often, they are described as “model”
children or as unusually “good.” But as a side
effect, they are also frequently anxious, insecure, and dependent on adults for approval.
Management techniques also have limitations. Most important is the need to carefully adjust to a child’s level of understanding. Younger children don’t always see the
connection between rules, explanations, and
their own behavior. Nevertheless, management techniques receive a big plus in another
area: There is a direct connection between
discipline and a child’s self-esteem.
How does discipline affect self-esteem? If
you regard yourself as a worthwhile person, you
have self-esteem. High self-esteem is essential for good emotional health. In elementary
school, children with high self-esteem tend to
be more popular, cooperative, and successful
in class. Children with low self-esteem are
more withdrawn and tend to perform below
average (Amato & Fowler, 2002).
Low self-esteem is related to physical punishment and the withholding of love. And
why not? What message do children receive if
a parent beats them or tells them they are not
worthy of love? Thus, it is best to minimize
physical punishment and avoid withdrawal of
love. In contrast, high self-esteem is promoted
by management techniques. Children who
feel that their parents support them emotionally tend to have high self-esteem (Amato &
Fowler, 2002; Nielsen & Metha, 1994).
Can self-esteem ever get too high? Yes it
can. According to clinical psychologist Maggie Mamen, many modern parents try to
“empower” their children by imposing few
limits on behavior, making them feel special, and giving them everything they want
(Mamen, 2004). But such good intentions
can backfire, leaving parents with children
who have developed an artificially high level
of self-esteem and a sense of entitlement.
That is, overly permissive parenting produces spoiled, self-indulgent children who
have little self-control (Baumrind, 1991).
Their sense of entitlement can lead them to
bully other children to get their way or even
to engage in criminal activity. As adults,
such children may become addicted to seeking ways to enhance their self-esteem. For
example, they may place excessive importance on being physically attractive, leading
to stress, drug and alcohol use, and eating
disorders (Crocker & Park, 2004).
Consistent Discipline. Individual parents
choose limits on behavior that are more
“strict” or less “strict.” But this choice is less
important than consistency (maintaining
stable rules of conduct). Consistent discipline
gives a child a sense of security and stability.
Inconsistency makes the child’s world seem
insecure and unpredictable.
What does consistent discipline mean in
practice? To illustrate the errors parents often
make, let’s consider a few examples of inconsistency (Fontenelle, 1989). The following
are mistakes to avoid:
Saying one thing and doing something
else. You tell the child, “Bart, if you don’t
eat your brussels sprouts you can’t have
any dessert.” Then you feel guilty and
offer him some dessert.
Making statements you don’t mean. “If
you don’t quiet down, I’m going to stop
the car and make you walk home.”
Changing no to yes, especially to quiet a
nagging child. A good example is the parent who first refuses to buy the child a toy
and later gives in and buys it.
Responding differently to the same misbehavior. One day a child is sent to his
room for fighting with his sister. The next
day the fighting is overlooked.
Inconsistency makes children feel angry
and confused because they cannot control the
consequences of their own behavior. Inconsistency also gives children the message: “Don’t
believe what I say because I usually don’t
mean it.”
Power assertion The use of physical punishment or coercion to enforce child discipline.
Withdrawal of love Withholding affection to
enforce child discipline.
Management techniques Combining praise,
recognition, approval, rules, and reasoning to
enforce child discipline.
Self-esteem Regarding oneself as a worthwhile
person; a positive evaluation of oneself.
Consistency With respect to child discipline,
the maintenance of stable rules of conduct.
114
CHAPTER 3
Using Discipline Constructively. At one time or
another, most parents use power assertion,
withdrawal of love, or management techniques
to control their children. Each mode of discipline has its place. However, physical punishment and withdrawal of love should always be
used with caution. Here are some guidelines:
1. Parents should separate disapproval of
the act from disapproval of the child.
Instead of saying, “I’m going to punish
you because you are bad,” say, “I’m upset
about what you did.”
2. State specifically what misbehavior you
are punishing. Explain why you have set
limits on this kind of conduct.
3. Punishment should never be harsh or
injurious. Don’t physically punish a
child while you are angry. Also remember that the message “I don’t love you
right now” can be more painful and
damaging than any spanking.
4. Punishment, such as a scolding or taking away privileges, is most effective
when done immediately. This statement is especially true for younger
children.
5. Spanking and other forms of physical
punishment are not particularly effective for children younger than age 2.
The child will only be confused and
frightened. Spankings also become
less effective after age 5 because they
tend to humiliate the child and breed
resentment.
6. As discussed earlier, many psychologists
believe that children should never be
spanked. If you do use physical punishment, reserve it for situations that
pose an immediate danger to younger
children; for example, when a child runs
into the street.
7. Remember, too, that it is usually more
effective to reward children when they
are being good than it is to punish them
for misbehavior.
After age 5, management techniques are
the most effective form of discipline, especially
techniques that emphasize communication
and the relationship between parent and child.
Communicating Effectively
with Children
Creative communication is another important ingredient of successful child management (Bath, 1996). Child expert Haim Ginott
(1965) believed that making a distinction
between feelings and behavior is the key to
clear communication. Because children (and
parents, too) do not choose how they feel, it is
important to allow free expression of feelings.
Accepting Feelings. The child who learns to
regard some feelings as “bad,” or unacceptable,
is being asked to deny a very real part of his or
her experience. Ginott encouraged parents to
teach their children that all feelings are appropriate; it is only actions that are subject to disapproval. Consider this typical conversation
excerpted from Ginott’s classic book (1965):
Son: I am stupid, and I know it. Look at my grades
in school.
Father: You just have to work harder.
Son: I already work harder and it doesn’t help. I
have no brains.
Father: You are smart, I know.
Son: I am stupid, I know.
Father: (loudly) You are not stupid!
Son: Yes, I am!
Father: You are not stupid. Stupid!
By debating with the child, the father
misses the point that his son feels stupid. It
would be far more helpful for the father to
encourage the boy to talk about his feelings.
For instance, he might say, “You really feel
that you are not as smart as others, don’t you?
Do you feel this way often?” In this way, the
child is given a chance to express his emotions
and to feel understood. The father might conclude by saying, “Look, son, in my eyes you are
a fine person. But I understand how you feel.
Everyone feels stupid at times.” He might also
offer some encouragement: “You’re improving. Look at the progress you’ve made.”
I-Messages. Child psychologist Thomas
Gordon (2000) believes that parents should
send I-messages to their children, rather than
you-messages.
What’s the difference? You-messages take
the form of threats, name-calling, accusing,
bossing, lecturing, or criticizing. Generally,
you-messages tell children what’s “wrong”
with them. An I-message tells children what
effect their behavior had on you. For example, after a hard day’s work, Maria wants to
sit down and rest awhile. She begins to relax
with a newspaper when her 5-year-old daughter starts banging loudly on a toy drum. Many
parents would respond with a you-message
such as “You go play outside this instant.”
(bossing) or “Don’t you ever make such a
racket when someone is reading.” (lecturing).
Gordon suggests sending an I-message such
as, “I am very tired, and I would like to read. I
feel upset and can’t read with so much noise.”
This forces the child to accept responsibility
for the effects of her actions (Dinkmeyer,
McKay, & Dinkmeyer, 1997).
Using Natural and Logical Consequences.
Sometimes events automatically discourage
misbehavior. For example, a child who refuses
to eat dinner will get uncomfortably hungry. A
child who throws a temper tantrum may gain
nothing but a sore throat and a headache if
the tantrum is ignored (Fontenelle, 1989). In
such instances, a child’s actions have natural
consequences (intrinsic effects). In situations
that don’t produce natural consequences, parents can set up logical consequences (rational
and reasonable effects). For example, a parent
might say, “We’ll go to the zoo when you’ve
picked up all those toys,” or “You can play with
your dolls as soon as you’ve taken your bath,”
or “You two can stop arguing or leave the table
until you’re ready to join us.”
The concept of logical, parent-defined consequences can be combined with I-messages to
handle many day-to-day instances of misbehavior. The key idea is to use an I-message to set up
consequences and then give the child a choice to
make: “Michelle, we’re trying to watch TV. You
can settle down and watch with us or go play
elsewhere. You decide which you’d rather do”
(Dinkmeyer, McKay, & Dinkmeyer, 1997).
How could Maria have dealt with her
5-year-old — the one who was banging on
a drum? A response that combines an
I-message with logical consequences would
be, “I would like for you to stop banging on
that drum; otherwise, please take it outside.”
If the child continues to bang on the drum
inside the house, then she has caused the toy
to be put away. If she takes it outside, she has
made a decision to play with the drum in a
way that respects her mother’s wishes. In this
way, both parent and child have been allowed
to maintain a sense of self-respect and a needless clash has been averted.
After you have stated consequences and let
the child decide, be sure to respect the child’s
choice. If the child repeats the misbehavior, you can let the consequences remain in
effect longer. But later, give the child another
chance to cooperate.
With all child management techniques,
remember to be firm, kind, consistent,
respectful, and encouraging. And most of all,
try every day to live the message you wish to
communicate.
Human Development
Effective Parenting
RECITE
1. Effective discipline gives children freedom within a structure of consistent and well-defined limits. T or F?
2. One good way to maintain consistency in child management is to
overstate the consequences for misbehavior. T or F?
3. Spankings and other physical punishments are most effective for
children under the age of 2. T or F?
4. Giving recognition for progress and attempts to improve is an example of parental _____________________________________.
5. I-messages are a gentle way of accusing a child of misbehavior.
T or F?
6. In situations where natural consequences are unavailable or do not
discourage misbehavior, parents should define logical consequences
for a child. T or F?
REFLECT
Critical Thinking
7. Several Scandinavian countries have made it illegal for parents to
spank their own children. Does this infringe on the rights of parents?
chapter in review
8. If power assertion is a poor way to discipline children, why do so
many parents use it?
Relate
What do you think are the best ways to discipline children? How would
your approach be classified? What are its advantages and disadvantages?
Parents can probably never be completely consistent. Think of a time
when your parents were inconsistent in disciplining you. How did it affect
you?
Think of a you-message you have recently given a child, family member, roommate, or spouse. Can you change it into an I-message?
Answers: 1. T 2. F 3. F 4. encouragement 5. F 6. T 7. Such laws are
based on the view that it should be illegal to physically assault any person, regardless of their age. Although parents may believe they have
a “right” to spank their children, it can be argued that children need
special protection because they are small, powerless, and dependent
(Durrant & Janson, 2005). 8. Most parents discipline their children in
the same ways that they themselves were disciplined. Parenting is
a responsibility of tremendous importance, for which most people
receive almost no training.
K N O WL E D GE B U I L D E R
115
Gateways to Human Development
Heredity (nature) and environment (nurture) are interacting forces
that are both necessary for human development. However, caregivers
can only influence environment.
Although neonates will die if not cared for at birth they are far from
helpless. They possess adaptive reflexes, are responsive to their
senses, begin to learn immediately, and are aware of their actions.
• The chromosomes and genes in each cell of the body carry
hereditary instructions. Most characteristics are polygenic and
reflect the combined effects of dominant and recessive genes.
• Maturation of the body and nervous system underlies the
orderly development of motor skills, cognitive abilities, emotions, and language.
• Many early skills are subject to the principle of readiness.
• Prenatal development is influenced by environmental factors,
such as various teratogens, including diseases, drugs, and radiation, as well as the mother’s diet, health, and emotions.
• During sensitive periods in development, infants are more sensitive to specific environmental influences.
• Early perceptual, intellectual, or emotional deprivation seriously retards development, whereas deliberate enrichment of
the environment has a beneficial effect on infants.
• In general, environment sets a reaction range within which
maturation unfolds.
• Temperament is hereditary. Most infants fall into one of three
temperament categories: easy children, difficult children, and
slow-to-warm-up children.
• A child’s developmental level reflects heredity, environment,
and the effects of the child’s own behavior.
• Infant development is strongly influenced by heredity.
However, environmental factors such as nutrition, parenting,
and learning are also important.
• The human neonate has a number of adaptive reflexes, including the grasping, rooting, sucking, and Moro reflexes.
• Tests in a looking chamber reveal a number of visual preferences in the newborn. The neonate is drawn to bright lights
and circular or curved designs.
• Infants prefer human face patterns, especially familiar faces. In
later infancy, interest in the unfamiliar emerges.
• The rate of maturation varies from person to person. Also, learning contributes greatly to the development of basic motor skills.
You-message Threatening, accusing, bossing, lecturing, or criticizing
another person.
I-message A message that states the effect someone else’s behavior
has on you.
Natural consequences The effects that naturally tend to follow a
particular behavior.
Logical consequences Reasonable consequences that are defined by
parents.
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CHAPTER 3
• Emotions develop in a consistent order, starting with generalized excitement in newborn babies. Three of the basic emotions — fear, anger, and joy — may be unlearned.
Early social development lays a foundation for relationships with parents, siblings, friends, and relatives and the emotional attachment of
human infants is a critical early event.
• Opportunities for social interaction increase as infants develop
self-awareness and they begin to actively seek guidance from
adults.
• Infant attachment is reflected by separation anxiety. The quality of attachment can be classified as secure, insecure-avoidant,
or insecure-ambivalent.
• Secure attachment is fostered by consistent care from parents
who are sensitive to a baby’s signals and rhythms.
• High-quality day care is not harmful and can even be helpful
to preschool children. Low-quality care can be risky.
• Meeting a baby’s affectional needs is as important as meeting
needs for physical care.
Studies suggest that parental styles have a substantial impact on
emotional and intellectual development.
• Three major parental styles are authoritarian, permissive, and
authoritative (effective). Authoritative parenting appears to
benefit children the most.
• Whereas mothers typically emphasize caregiving, fathers tend
to function as playmates for infants. Both caregiving styles
contribute to the competence of young children.
• The ultimate success of various parenting styles depends on
what culture or ethnic community a child will enter.
• Parenting styles vary across cultures.
Language development proceeds from crying to cooing, then babbling, the use of single words, and then to telegraphic speech.
• Learning to use language is a cornerstone of early intellectual
development.
• The underlying patterns of telegraphic speech suggest a biological predisposition to acquire language. This innate tendency is augmented by learning.
• Prelanguage communication between parent and child
involves shared rhythms, nonverbal signals, and turn-taking.
• Motherese or parentese is a simplified, musical style of speaking that parents use to help their children learn language.
The intellect of a child is less abstract than that of an adult. Jean
Piaget theorized that children mature through a fixed series of cognitive stages by applying a combination of assimilation and accommodation. Lev Vygotsky emphasized the role of interactions with more
competent partners.
• Piaget held that children mature through a fixed series of
cognitive stages. The stages and their approximate age ranges
are sensorimotor (0–2), preoperational (2–7), concrete operational (7–11), and formal operations (11–adult).
• Caregivers should offer learning opportunities that are appropriate for a child’s level of cognitive development.
• Learning principles provide an alternate explanation that
assumes cognitive development is continuous; it does not
occur in stages.
• Recent studies of infants under the age of 1 year suggest that
they are capable of thought well beyond that observed by
Piaget.
• Lev Vygotsky’s sociocultural theory emphasizes that a child’s
mental growth takes place in a child’s zone of proximal development, where a more skillful person may scaffold the child’s
progress. As children rely on adults to help them discover new
skills and principles they learn cultural beliefs and values.
Adolescents must form their identity and values at a time when they
are also dealing with puberty and transition to adulthood is occurring
at ever-later ages.
• The timing of puberty can complicate the task of identity formation, a major task of adolescence.
• Transitioning from childhood to adulthood requires the
formation of a personal identity, the major life task of
adolescence.
• Identity formation is even more challenging for adolescents of
ethnic descent.
• In Western industrialized societies the transition into adulthood is further complicated as it is increasingly delayed well
into the 20s.
As in other types of development, we develop morals and values as we
grow through several levels.
• Lawrence Kohlberg identified preconventional, conventional,
and postconventional levels of moral reasoning.
• Developing mature moral standards is also an important task
of adolescence.
• Most people function at the conventional level of morality, but
some never get beyond the selfish, preconventional level. Only
a minority of people attain the highest, or postconventional
level, of moral reasoning.
• Carol Gilligan distinguished between Kohlberg’s justice perspective and a caring perspective. Mature adult morality likely
involves both.
Erik Erikson identified a series of challenges that occur across the lifespan. These range from a need to gain trust in infancy to the need to
live with integrity in old age.
• Personal development does not end after adolescence. Periods
of stability and transition occur throughout adulthood.
• We face a specific “crisis,” or psychosocial dilemma, at each life
stage.
• Successful resolution of the dilemmas produces healthy development, whereas unsuccessful outcomes make it harder to deal
with later crises.
Human Development
Well-being during adulthood consists of six elements: self-acceptance,
positive relations with others, autonomy, environmental mastery,
having a purpose in life, and continued personal growth.
• Physical aging starts early in adulthood. Every adult must find
ways to successfully cope with aging.
• Only a minority of people have a midlife crisis, but midlife
course corrections are more common.
• Even if no crisis occurs, people tend to move through repeated
cycles of stability and transition throughout adulthood.
• Intellectual declines associated with aging are limited, at least
through one’s 70s. This is especially true of individuals who
remain mentally active.
• Successful lives are based on happiness, purpose, meaning, and
integrity.
• Ageism refers to prejudice, discrimination, and stereotyping
on the basis of age. It affects people of all ages but is especially
damaging to older people. Most ageism is based on stereotypes, myths, and misinformation.
Typical emotional reactions to impending death include denial, anger,
bargaining, depression, and acceptance, but not necessarily in that
order or in every case.
117
Web Resources
For an up-to-date list of direct links to interesting sites, including
those listed here, visit the student companion site for this book at
www.cengage.com/psychology/coon
Human Genome Project Learn more about your human genetic
heritage.
Crack Babies A photostory by Ken Kobre.
Scaffolding as a Teaching Strategy Download a paper on the application of Vygotsky’s idea of scaffolding to teaching.
A Positive Approach to Identity Formation of Biracial Children
Join the debate about multiethnicity and identity formation.
Delayed Adulthood Read two articles about delayed adulthood.
Kohlberg Dilemmas Try your hand at answering several moral
dilemmas.
Hospice A website of information about death, bereavement, and
hospices.
Discipline: Logical & Natural Consequences Read about ways to
effectively structure discipline.
• Death is a natural part of life. There is value in understanding
it and accepting it.
Positive parent-child interactions occur when parents spend enjoyable time encouraging their children in a loving and mutually respectful fashion.
• Effective parental discipline tends to emphasize child management techniques (especially communication), rather than
power assertion or withdrawal of love.
• Consistency is also an important aspect of effective parenting.
• Effective parents allow their children to express their feelings
but place limits on their behavior.
• Much misbehavior can be managed by use of I-messages and
the application of natural and logical consequences.
Interactive Learning
Introduction to Psychology: Gateways to Mind and Behavior Book
Companion Website
www.cengage.com/psyc hology/coon
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practice quizzes, web links, and more to help you study.
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Spend time on what you need to master rather than on information you already have learned. Take a pre-test for this chapter, and
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Try it out! Go to www.cengage.com.com/login to sign in with an
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CHAPTER
4
Sensation and Reality
Gateway Theme
Sensory systems link us to the external world and shape the flow of information
to the brain.
Tim Flach/Getty Images
Gateway Questions
• In what ways are our senses limited?
• How does the visual system function?
• How do we perceive colors?
• How do we adjust to the dark?
• What are the mechanisms of hearing?
118
•
•
•
•
How do the chemical senses operate?
What are the somesthetic senses?
Why are we more aware of some sensations than others?
How can pain be reduced in everyday situations?
preview
Can’t You Hear the Bats?
One of your authors once stood at dusk at the mouth of a huge
limestone cave on the island of Borneo. For some 20 minutes,
fruit bats streamed out of the cave until a dense cloud of half
a million bats swirled overhead in the gathering darkness.
Besides the sheer spectacle, what most struck him was the
silence. Aside from the occasional whisper of bat wings swishing by his ear, he heard nothing. And yet every single bat was
shouting — at a pitch so high a human being couldn’t hear it.
Echoes from those shouts allowed the bats to avoid colliding
with each other. At that moment, he was keenly aware of the
limitations of his senses.
Do you imagine that the ear is like a digital recorder or the
eye is like a camera, giving us a completely accurate “picture” of
reality? Perhaps you already understand that this view greatly
oversimplifies how we sense and perceive the world. Certainly,
as our bat story shows, the senses do not capture complete information about the environment. While this may seem to be some
sort of evolutionary oversight, just the opposite is the case. We
collect enough sensory information to survive while reducing
the amount of sensory information bombarding the brain. This
selectivity helps prevent the brain from overloading.
Regardless, at this very moment you are bathed in a swirling kaleidoscope of electromagnetic radiation, heat, pressure,
vibrations, molecules, and mechanical forces. Without the
senses, all of this would seem like nothing more than a void of
silence and darkness. The next time you drink in the beauty of
a sunset, a flower, or a friend, remember this: Sensation makes
it all possible.
Psychophysics — The
Limits of Sensibility
tions into sound waves. Pluck a string and the guitar will produce a
sound. However, stimuli that don’t cause the string to move will have
no effect. For instance, if you shine a light on the string, or pour cold
water on it, the guitar will remain silent. (The owner of the guitar,
however, might get quite loud at this point!) Thus, the eye transduces electromagnetic radiation, the ear transduces sound waves, and
so on. Many other types of stimuli cannot be sensed directly because
we have no sense receptors to transduce their energy.
For example, humans cannot sense the bioelectric fields of
other living beings, but sharks have special organs that can (Fields,
2007). (Do they hear the fields or feel them or what?) Similarly,
humans can transduce only visible light, which is a tiny slice of the
electromagnetic spectrum (entire spread of electromagnetic wavelengths). The spectrum also includes infrared and ultraviolet light,
radio waves, television broadcasts, gamma rays, and other energies
(look ahead at Figure 4.3). In contrast, the eyes of honeybees
transduce parts of the electromagnetic spectrum invisible to
humans. As you can see, our rich sensory experience is only a small
part of what could be sensed and what some animals can sense.
Gateway Question: In what ways are our senses limited?
Physical energy, in the form of light waves or heat or sound waves,
stimulates your senses. An instant later you see a snowball whiz
past your nose or feel the warmth of the sun on your face or hear a
catchy tune on the radio. In that instant, a remarkable series of
events will have transpired as you detect, analyze, and interpret
sensory information.
In an approach called psychophysics, physical energy (such as
sound waves or electromagnetic radiation) is measured and related
to dimensions of the resulting sensations we experience (such as
loudness or brightness). Psychophysical investigations have
revealed much about our sensory capacities and their limits.
Our eyes, for example, provide us with stunningly wide access
to the world. In one instant you can view a star light-years away,
and in the next, you can peer into the microscopic universe of a
dewdrop. Yet, vision also dramatically narrows what we can
observe. Like the other senses, vision acts as a data reduction system. Your senses send only the most important data to your brain
(Sekuler & Blake, 2006). Before we examine specific senses in
more detail, let’s explore how the senses reduce the amount of
information the brain must process.
•
Absolute Thresholds
Before you can experience a sensation, a stimulus (physical energy)
must be above a certain minimum intensity. The necessary minimum defines the absolute threshold for a sensory system. For
Transduction
How does data reduction take place? To begin, our senses limit what
we can experience because they do not transduce all the physical energies surrounding us. Sensory receptors, such as the eyes and ears, are
biological transducers, devices that convert one kind of energy into
another (Fain, 2003). For example, a guitar transduces string vibra-
Psychophysics Study of the relationship between physical stimuli and
the sensations they evoke in a human observer.
Transducers Devices that convert one kind of energy into another.
Absolute threshold The minimum amount of physical energy
necessary to produce a sensation.
119
CHAPTER 4
Table 4.1
• Absolute Thresholds
Sensory Modality
Absolute Threshold
Vision
Candle flame seen at 30 miles on a clear dark
night
Hearing
Tick of a watch under quiet conditions at 20 feet
Taste
1 teaspoon of sugar in 2 gallons of water
Smell
1 drop of perfume diffused into a three-room
apartment
Touch
A bee’s wing falling on your cheek from 1 centimeter above
© Robert Rattner
120
From Galanter, 1962.
example, very soft sounds (which could be heard if they were just
a little louder) fall below the absolute threshold for human hearing. Of course, owls have much lower absolute thresholds for hearing, which allows them to hunt at night.
What is the quietest sound that humans can hear? The weakest light
that we can see? The lightest touch that we can feel? Testing for absolute
thresholds shows just how sensitive we are. For example, it only takes
three photons of light striking visual receptors at the back of the eye
to produce a sensation. A photon (FOE-tahn: one quantum of
energy) is the smallest possible “package” of light. Responding to
three photons is like seeing a candle flame 30 miles away! Table 4.1
gives approximate absolute thresholds for the five major senses.
Some sensory systems have upper limits as well as lower ones.
For example, if we test for pitch sensitivity (higher and lower
tones), we find that humans can hear sounds down to 20 hertz
(vibrations per second) and up to about 20,000 hertz. This is an
impressive range — from the lowest rumble of a pipe organ to the
highest squeak of a stereo “tweeter.” On the lower end, the threshold is as low as practical. If your ears could sense tones below
20 hertz, you would hear the movements of your own muscles.
Imagine how disturbing it would be to hear your body creak and
groan like an old ship as you move.
The 20,000 hertz upper threshold for human hearing, on the
other hand, could easily be higher. Bats, dogs, cats, and other animals can hear sounds well above this limit. That’s why a “silent” dog
whistle (which may make sounds as high as 40,000 to 50,000 hertz)
can be heard by dogs but not by humans. For dogs the sound exists.
For humans it is beyond awareness. It’s easy to see how thresholds
define the limits of the sensory world in which we live. (If you want
to buy a stereo system for your dog, you will have a hard time finding one that reproduces sounds above 20,000 hertz!)
Wouldn’t the absolute threshold be different for different people?
Not only do absolute thresholds vary for different people, they
also change from time to time for a single person. The type of
stimulus, the state of your nervous system, and the costs of false
“detections” all make a difference (Goldstein, 2007). Emotional
factors are also important. Unpleasant stimuli, for example, may
raise the threshold for recognition.
Is “subliminal” perception possible? Yes, under limited circumstances. Anytime information is processed below the normal limen
(LIE-men: threshold or limit) for awareness, it is subliminal. Subliminal perception was demonstrated by a study in which college
•
Absolute thresholds define the sensory worlds of humans and animals, sometimes with serious consequences. The endangered Florida manatee (“sea cow”)
is a peaceful, plant-eating creature that can live for more than 60 years. For the
last decade, the number of manatees killed by boats has climbed alarmingly. The
problem? Manatees have poor sensitivity to the low-frequency sounds made by
slow-moving boats. Current laws require boats to slow down in manatee habitats, which may actually increase the risk to these gentle giants (Gerstein, 2002).
students saw photos of a person flashed on a screen. Each time
before the face appeared, it was preceded by a subliminal image that
was shown for just a fraction of a second. Some were images that
made viewers feel good (such as cute kittens). Others made them
feel bad (for example, a face on fire). All the emotional images were
flashed too briefly to be recognized. Nevertheless, they altered the
impressions students formed of the target person (Krosnick et al.,
1992). Apparently, some emotional impact gets through, even when
a stimulus is below the level of conscious awareness (Arndt, Allen, &
Greenberg, 2001). To find out if such effects could be applied to
advertising, read “Subliminal Seduction or Subliminal Myths?”
Difference Thresholds
Psychophysics also involves the study of difference thresholds.
Here we are asking, “How much must a stimulus change (increase
or decrease) before it becomes just noticeably different?” The
study of just noticeable differences (JNDs) led to one of psychology’s first natural “laws.” Weber’s (VAY-bears) law can be roughly
stated as follows: The amount of change needed to produce a JND
is a constant proportion of the original stimulus intensity. Here are
some Weber’s proportions for common judgments:
Pitch
Weight
Loudness
Taste
1/333 (1/3 of 1 percent)
1/50 (2 percent)
1/10 (10 percent)
1/5 (20 percent)
Notice how much more sensitive hearing is than taste. Very small
changes in pitch and loudness are easy to detect. If a voice or a musical instrument is off pitch by 1/3 of 1 percent, you’ll probably notice
it. For taste, we find that a 20-percent change is necessary to produce
a JND. If a cup of coffee has 5 teaspoons of sugar in it, you will have
to add 1 more (1/5 of 5) before it will be noticeably sweeter. If you’re
salting soup, it takes a lot of cooks to spoil the broth!
Sensation and Reality
121
CRIT ICA L T H I N KI N G
Subliminal Seduction or Subliminal Myth?
performed no better than students who
just listened to relaxing ocean sounds without subliminal messages and students who
listened to nothing at all (Russell, Rowe, &
Smouse, 1991). In this instance, subliminal
messages had no effect, even when people
wanted to be influenced. In most cases,
people who think they have been helped by
subliminal messages have likely experienced
nothing more than a placebo effect (Froufe &
Schwartz, 2001).
However, before writing off subliminal
advertising altogether, let’s consider the work
of psychologist Johan Karremans and his colleagues (Karremans, Stroebe, & Claus, 2006).
They suggest that only simple messages,
such as single words, can be processed subliminally, which is why subliminal self-help
materials are usually ineffective. They also
provide evidence that subliminally flashing
the brand name of a drink can increase the
likelihood that people will buy it, but only if
they are already thirsty. Perhaps subliminal
advertising can work under limited circumstances. Nevertheless, advertisers are still
better off using the loudest, clearest, most
attention-demanding stimuli available — as
most do (Smith & Rogers, 1994).
© Michael Maslin from cartoon bank.com. All Rights Reserved.
Could subliminal perception ever be used
against us? The sensationalistic book
Subliminal Seduction (Key, 1973) voiced popular fears of attempts to influence us through
subliminal messages embedded in advertising. But could it work?
In a famous early attempt, a New Jersey
theater flashed the words Eat popcorn and
Drink Coca-Cola on the screen for 1/3,000 second every 5 seconds during movies. Dramatic
claims that popcorn and Coke sales increased
as a result later turned out to be falsehoods.
The advertising “expert” responsible admitted he faked the whole thing. By lying about
his ability to control audiences, he had hoped
to gain customers for his marketing business
(Pratkanis, 1992; Shrum, 2004). Regardless,
the possibility of subliminal seduction was so
horrifying that such advertising was banned
in the United States, Britain, and Australia
(Karremans, Stroebe, & Claus, 2006).
Despite these fears, some businesses
actually sell subliminal messages to people
who want them to work. Each year, consumers spend many millions of dollars on
so-called subliminal self-help tapes and CDs
(Pratkanis & Aronson, 2001). “Subliminal messages” embedded in relaxing music or the
soothing sounds of ocean waves purportedly influence “subconscious motivation”
to help listeners lose weight, relieve pain,
find romance, succeed financially, improve
grades, and so forth.
In one study, students who listened to
subliminal messages meant to improve
their study habits, and, hence, their grades,
Sensory Analysis and Coding
What we experience is greatly influenced by sensory analysis. As
they process information, the senses divide the world into important perceptual features (basic stimulus patterns). For vision,
such features include lines, shapes, edges, spots, colors, and other
patterns (Hubel & Wiesel, 2005). Look at Figure 4.1 and notice
how eye-catching the single vertical line is among a group of
slanted lines. This effect, which is called pop-out, occurs because
your visual system is highly sensitive to perceptual features such as
line orientation (Adler & Orprecio, 2006).
In some instances, the senses act as feature detectors because
they are attuned to very specific stimuli. Frog eyes, for example,
are highly sensitive to small, dark, moving spots. In other words,
•
Subliminal perception Perception of a stimulus below the threshold
for conscious recognition.
Difference threshold A change in stimulus intensity that is detectable
to an observer.
Just noticeable difference (JND) Any noticeable difference in a stimulus.
Weber’s law The just noticeable difference is a constant proportion of
the original stimulus intensity.
Sensory analysis Separation of sensory information into important
elements.
Perceptual features Basic elements of a stimulus, such as lines, shapes,
edges, or colors.
122
CHAPTER 4
including pressure — into visual features. As a result, you experience light sensations, not pressure. Also important in producing
this effect is sensory localization in the brain.
Sensory localization means that the type of sensation you experience depends on which brain area is activated. Some brain areas
receive visual information, others receive auditory information, and
still others receive taste or touch. (See Chapter 2, pages 63–67.)
Knowing which brain areas are active tells us, in general, what
kinds of sensations you are feeling.
Sensory localization makes it possible to artificially restore
sight, hearing, or other senses. For example, in July 2006, a woman
named Cheri Robinson became the sixteenth person in the world
with an implant that allows a miniature television camera to send
electrical signals to her brain’s visual cortex ( Figure 4.2). She can
now “see” 100 dots of light. Like a sports scoreboard, these lights
can be used to form crude letters (Warren & Normann, 2005).
Eventually, increasing the number of dots could make reading and
“seeing” large objects, such as furniture and doorways, possible.
It is fascinating to realize that “seeing” and “hearing” take place
in the brain, not in the eye or ear. Information arriving from the
sense organs creates sensations. When the brain organizes sensations into meaningful patterns, we speak of perception, which
will be covered in Chapter 5. It’s now time to examine each of the
senses in more detail. In the next section, we will begin with vision,
which is perhaps the most magnificent sensory system of all.
Before you read more, it might be a good idea to stop and review
some of the ideas we have covered.
•
Figure 4.1 Visual pop-out. Pop-out is so basic that babies as young as 3
•months
respond to it.
(Adapted from Adler & Orprecio, 2006.)
they are basically “tuned” to detect bugs flying nearby (Lettvin,
1961). But the insect (spot) must be moving, or the frog’s “bug
detectors” won’t work. A frog could starve to death surrounded
by dead flies.
After they have selected and analyzed information, sensory
systems must code it. Sensory coding refers to changing important
features of the world into messages understood by the brain
(Hubel & Wiesel, 2005). To see coding at work, try closing your
eyes for a moment. Then take your fingertips and press firmly on
your eyelids. Apply enough pressure to “squash” your eyes slightly.
Do this for about 30 seconds and observe what happens. (Readers
with eye problems or contact lenses should not try this.)
Did you “see” stars, checkerboards, and flashes of color? These
are called phosphenes (FOSS-feens: visual sensations caused by
mechanical excitation of the retina). They occur because the eye’s
receptor cells, which normally respond to light, are also
somewhat sensitive to pressure. Notice though, that
the eye is only prepared to code stimulation —
KNOWL E DG E B U I L DE R
Sensation and Psychophysics
RECITE
1. Sensory receptors are biological ___________________, or devices
for converting one type of energy to another.
2. The minimum amount of stimulation necessary for a sensation to
occur defines the ___________________ ______________________.
Continued
Visual
cortex
Electrodes
Actual image
Cameras
Perceived image
• Figure 4.2 An artificial visual system.
Sensation and Reality
INVISIBLE LONG WAVES
VISIBLE LIGHT SPECTRUM
INVISIBLE SHORT WAVES
Infrared rays
(beyond red)
1500
1000
123
Ultraviolet rays
(beyond violet)
700
Radio
600
TV
Microwaves
500
Infrared
400
U-V
X-rays
300
Gamma Cosmic
rays
rays
• Figure 4.3 The visible spectrum.
3. Subliminal stimuli have been shown to have an effect on the behavior of viewers. T or F?
4. Lettvin found that a frog’s eyes are especially sensitive to phosphenes. T or F?
5. Important features of the environment are transmitted to the brain
through a process known as
a. phosphenation
b. coding
c. detection
d. programming
REFLECT
Critical Thinking
6. Is a doorbell a transducer?
7. If the human ear were more sensitive than it is now, our hearing
would be impaired. How could this be true?
8. When promoters of self-help “subliminal tapes” are challenged to
provide evidence that their products work, what study do you think
they most often cite?
Relate
How does sensation affect what you are experiencing right now? What if
data reduction didn’t occur? What if you could transduce other energies?
What if your senses were tuned to detect different perceptual features?
What if your absolute thresholds were higher or lower for each sense?
How would the sensory world you live in change?
Vision — Catching Some Rays
Gateway Question: How does the visual system function?
In the morning when you awaken and open your eyes you effortlessly become aware of the visual richness of the world around you.
But the ease with which normally sighted people can see conceals
incredible complexity. Vision is an impressive sensory system,
worthy of a detailed discussion.
What are the basic dimensions of light and vision? As we have
noted, various wavelengths of light make up the visible spectrum
(the narrow spread of electromagnetic energies to which the eyes
respond). Visible light starts at “short” wavelengths of 400 nanometers (nan-OM-et-er: one billionth of a meter), which we sense
as purple or violet. Longer light waves produce blue, green, yellow, orange, and red, which has a wavelength of 700 nanometers
( Figure 4.3).
The term hue refers to the basic color categories of red, orange,
yellow, green, blue, indigo, and violet. As just noted, various hues
(or color sensations) correspond to the wavelength of the light
that reaches our eyes (Sekuler & Blake, 2006). White light, in
contrast, is a mixture of many wavelengths. Hues (colors) from a
narrow band of wavelengths are very saturated, or “pure.” (An
•
Sensory coding Codes used by the sense organs to transmit
information to the brain.
Sensation A sensory impression; also, the process of detecting physical
energies with the sensory organs.
Perception The mental process of organizing sensations into
meaningful patterns.
Visible spectrum The narrow spread of the electromagnetic spectrum
to which the eyes are sensitive.
Answers: 1. transducers 2. absolute threshold 3. T 4. F 5. b 6. In a broad
sense, it is. The button converts mechanical energy from your finger
into an electrical signal that is converted again into mechanical energy
in order to strike a bell; the physical vibrations of the bell then produce
sound waves that are transduced into nerve impulses by the ears of the
person in the house. 7. Under ideal conditions, vibrations of the eardrum
as small as one billionth of a centimeter (one tenth the diameter of a
hydrogen atom) can be heard. Therefore, if your ears were more sensitive, they would convert the random movement of air molecules into a
constant roaring or hissing noise. 8. Good guess! That’s right, it’s still the
faked “Eat popcorn/drink Coca-Cola” study (Pratkanis, 1992).
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CHAPTER 4
intense “fire-engine” red is more saturated than a muddy “brick”
red.) A third dimension of vision, brightness, corresponds roughly
to the amplitude, or height of light waves. Waves of greater amplitude are “taller,” carry more energy, and cause the colors we see to
appear brighter or more intense. For example, the same “brick” red
would look bright under intense, high-energy illumination and
drab under dim light.
Structure of the Eye
Although the visual system is much more complex than any digital
camera, both cameras and eyes have a lens to focus images on a
light-sensitive layer at the back of a closed space. In a camera, this
layer is the digital image sensor. In the eye, it is a layer of photoreceptors (light-sensitive cells) in the retina, an area about the size
and thickness of a postage stamp ( Figure 4.4).
How does the eye focus? Most focusing is done at the front of the
eye by the cornea, a clear membrane that bends light inward. The
lens makes additional, smaller adjustments. Your eye’s focal point
changes when muscles attached to the lens alter its shape. This
•
Ciliary
muscle
Aqueous
humor
Fovea
Blind spot
Iris
Pupillary
opening
Optic
nerve
Cornea
process is called accommodation. In cameras, focusing is done
more simply — by changing the distance between the lens and the
image sensor.
Visual Problems
Focusing is also affected by the shape of the eye. If your eye is too
short, nearby objects will be blurred, but distant objects will be
sharp. This is called hyperopia (HI-per-OPE-ee-ah: farsightedness). If your eyeball is too long, images fall short of the retina and
you won’t be able to focus distant objects. This results in myopia
(my-OPE-ee-ah: nearsightedness). When the cornea or the lens is
misshapen, part of vision will be focused and part will be fuzzy. In
this case, the eye has more than one focal point, a problem called
astigmatism (ah-STIG-mah-tiz-em). All three visual defects can
be corrected by reshaping the cornea through laser eye surgery or
by placing glasses (or contact lenses) in front of the eye to change
the path of light ( Figure 4.5).
As people age, the lens becomes less flexible and less able to
accommodate. The result is presbyopia (prez-bee-OPE-ee-ah:
old vision, or farsightedness due to aging). Perhaps you have seen
a grandparent or older friend reading a newspaper at arm’s length
because of presbyopia. If you now wear glasses for nearsightedness,
you may need bifocals as you age. ( Just like your authors. Sigh.)
Bifocal lenses correct near vision and distance vision.
•
Light Control
There is one more major similarity between the eye and a camera.
In front of the lens in both is a mechanism that controls the
amount of light entering. In the eye, this mechanism is the iris; in
a camera, it is the diaphragm ( Figure 4.6). The iris is a colored
circular muscle that gives your eyes their blue or brown or green
color. By expanding and contracting, the iris changes the size of
the pupil (the opening at the center of the eye).
With some cameras, you can adjust the sensitivity of the digital
image sensor. The sensitivity of the retina also changes in brighter
•
Retinal arteries
and veins
Lens
Retina
• Figure 4.4 The human eye, a simplified view.
Point of
focus
Distant point
Near point
Misshapen cornea
Misshapen lens
Part of image is
focused; part is not
Concave
lens
(a) Nearsighted Eye
•
Figure 4.5
Convex
lens
(b) Farsighted Eye
Nonsymmetrical
lens
(c) Astigmatic Eye
Visual defects and corrective lenses: (a) A myopic (longer than usual) eye. The concave lens spreads light rays just enough
to increase the eye’s focal length. (b) A hyperopic (shorter than usual) eye. The convex lens increases refraction (bending), returning the
point of focus to the retina. (c) An astigmatic (lens or cornea not symmetrical) eye. In astigmatism, parts of vision are sharp and parts are
unfocused. Lenses to correct astigmatism are unsymmetrical.
Sensation and Reality
125
•
120 million, can’t detect colors ( Figure 4.7). Pure rod vision is
black and white. However, the rods are much more sensitive to
light than the cones are. The rods therefore allow us to see in very
dim light.
Notice in Figure 4.7 that light does not fall directly on the
rods and cones. It must pass through the outer layers of the retina.
Note, too, that the rods and cones face the back of the eye! Only
Figure 4.6 The iris and diaphragm.
about one half of the light falling on the front of the eye ever
reaches the rods and cones — testimony to the eye’s amazing light
sensitivity.
Surprisingly, the retina has a “hole” in it: Each eye has a blind
Direction of light
spot because there are no receptors where the optic nerve passes
out of the eye and blood vessels enter ( Figure 4.7). The blind
spot shows that vision depends greatly on the brain. If you close
one eye, part of what you see will fall on the blind spot of your
open eye ( Figure 4.8a). Why isn’t there a gap in your
vision? The answer is that the visual cortex of the
brain actively fills in the gap with patterns from
Fibers of the
optic nerve
surrounding areas ( Figure 4.8b). By closing
one eye, you can visually “behead” other peoGanglion cell
ple by placing their images on your blind
Amacrine cell
Retina
spot. (Just a hint for some classroom fun.)
The brain can also “erase” distracting information. Roll your eyes all the way to the
Bipolar
right and then close your right eye. You
neuron
Horizontal
should clearly see your nose in your
cell
left eye’s field of vision. Now, open
Retina
your right eye again and your nose
Photoreceptor
will nearly disappear as your brain
cells:
Cone
disregards its presence.
Optic
Rod
nerve
It’s tempting to think of vision
Pigment layer
as a movie-like projection of “picof retina
tures” to the brain. However, this mistaken notion
Choroid layer
immediately raises the question, “Who’s watching
Sclera
the movie?” From the retina on, vision becomes quite
Figure 4.7 Anatomy of the retina. The retina lies behind the vitreous humor,
unlike a digital camera, which merely records and displays the
which is the jelly-like substance that fills the eyeball. The rods and cones are much
digital images it has captured. Instead, vision is a complex system
•
•
•
•
•
Omikron/Photo Researchers, Inc.
n of ses
ctio
l
Dire e impu
nerv
•
smaller than implied here. The smallest are 1 micron (one millionth of a meter)
wide. The lower-left photograph shows rods and cones as seen through an electron
microscope. In the photograph the cones are colored green and the rods blue.
Retina The light-sensitive layer of cells at the back of the eye.
or dimmer light, but the retina can only adapt slowly. By making
rapid adjustments, the iris allows us to move quickly from darkness to bright sunlight, or the reverse. In dim light the pupils dilate
(enlarge), and in bright light they constrict (narrow). When the
iris is wide open, the pupil is 17 times larger than at its smallest.
Were it not for this, you would be blinded for some time after
walking into a darkened room.
Accommodation Changes in the shape of the lens of the eye.
Hyperopia Difficulty focusing nearby objects (farsightedness).
Myopia Difficulty focusing distant objects (nearsightedness).
Astigmatism Defects in the cornea, lens, or eye that cause some areas
of vision to be out of focus.
Presbyopia Farsightedness caused by aging.
Iris Circular muscle that controls the amount of light entering the eye.
Rods and Cones
Pupil The opening at the front of the eye through which light passes.
The eye has two types of “image sensors,” consisting of receptor
cells called rods and cones (Goldstein, 2007). The 5 million cones
in each eye work best in bright light. They also produce color
sensations and fine details. In contrast, the rods, numbering about
Cones Visual receptors for colors and daylight visual acuity.
Rods Visual receptors for dim light that produce only black and white
sensations.
Blind spot An area of the retina lacking visual receptors.
126
CHAPTER 4
4.8 Experiencing the blind spot.
•(a)Figure
With your right eye closed, stare at the
upper-right cross. Hold the book about 1 foot
from your eye and slowly move it back and
forth. You should be able to locate a position
that causes the black spot to disappear. When
it does, it has fallen on the blind spot. With a
little practice you can learn to make people or
objects you dislike disappear too! (b) Repeat
the procedure described, but stare at the lower
cross. When the white space falls on the blind
spot, the black lines will appear to be continuous. This may help you understand why you
do not usually experience a blind spot in your
visual field.
(a)
(b)
for analyzing patterns of light. Thanks to the Nobel Prize–
winning work of biopsychologists David Hubel and Torsten
Wiesel, we now know that vision acts more like an incredibly
advanced computer than a television or movie camera.
Hubel and Wiesel directly recorded the activities of single cells
in the brain’s visual cortex in cats and monkeys. As they did, they
noted the area of the retina to which each cell responded. Then
they aimed lights of various sizes and shapes at the retina and
recorded how often the corresponding brain cell fired nerve
impulses ( Figure 4.9a).
The results were fascinating. Many brain cells responded only
to lines of a certain width or orientation. These same cells didn’t
get the least bit “excited” over a dot of light or overall illumination
( Figure 4.9b). Other cells responded only to lines at certain
angles, or lines of certain lengths, or lines moving in a particular
direction (Hubel & Wiesel, 1979).
The upshot of such findings is that cells in the brain, like the
frog’s retina described earlier, act as feature detectors. The brain
seems to first analyze information into lines, angles, shading,
movement, and other basic features. Then, other brain areas combine these features into meaningful visual experiences. (This concept is discussed further in Chapter 5.) Reading this page is a
direct result of such feature analysis. Given the size of the task, it’s
little wonder that as much as 30 percent of the human brain may
be involved in vision. (To further follow the pathways visual infor-
•
•
mation takes through the brain, see “Blindsight: The ‘What’ and
the ‘Where’ of Vision.”)
Visual Acuity
The rods and cones also affect visual acuity, or sharpness. The
cones lie mainly at the center of the eye. In fact, the fovea (FOEvee-ah: a small cup-shaped area in the middle of the retina) contains only cones — about 50,000 of them. Like a newspaper photograph made of many small dots, the tightly packed cones in the
fovea produce the sharpest images. Normal acuity is designated as
20/20 vision: At 20 feet in distance, you can distinguish what the
average person can see at 20 feet ( Figure 4.11). If your vision is
20/40, you can only see at 20 feet what the average person can see
at 40 feet. If your vision is 20/200, everything is a blur and you
need glasses! Vision that is 20/12 would mean that you can see at
20 feet what the average person must be 8 feet nearer to see, indicating better than average acuity. American astronaut Gordon
Cooper, who claimed to see railroad lines in northern India from
100 miles above, had 20/12 vision.
•
Peripheral Vision
What is the purpose of the rest of the retina? Areas outside the fovea
also get light, creating a large region of peripheral (side) vision.
The rods are most numerous about 20 degrees from the center of
the retina, so much of our peripheral vision is rod vision. Although
Receptive field for
single cell in cortex
Total visual field
4.9 (a) A “typical” brain
•cellFigure
responds to only a small area of the
total field of vision. In this example, the
cell responds to stimuli that fall above
and left of the center of vision. The bar
graph (b) illustrates how a brain cell may
act as a feature detector. Notice how the
cell primarily responds to just one type of
stimulus. (Adapted from Hubel, 1979.)
Center of vision
(a)
Frequency of nerve impulses
Stimulus
High
Low
Test stimuli
(b)
Sensation and Reality
127
B RAIN W AVES
Blindsight: The “What” and the “Where” of Vision
was, but she had enough sight to know where
it was in her visual field (James et al., 2003).
What patients like D. F. teach us is that the
brain has assigned the job of seeing to different brain regions (Deco, Rolls, & Horowitz,
2004). One series of regions, the ventral pathway, is responsible for the “what” of vision,
whereas another series of regions, the dorsal pathway, is responsible for the “where” of
vision ( Figure 4.10). D. F. suffered damage
in her ventral pathway so she could not
process the “what” of vision, but her
intact dorsal pathway could still
process the “where” of vision.
•
pathway
Ventral t)
(Wha
B
(a)
K
• Figure 4.10 The ventral and dorsal
The rods are also highly responsive to dim light. Because most
rods are 20 degrees to each side of the fovea, the best night vision
comes from looking next to an object you wish to see. Test this
yourself some night by looking at, and next to, a very dim star.
C
E
(b)
S
Primary
visual
cortex
visual pathways.
F
L
What happens if someone suffers brain
damage to the dorsal pathway? In a rare case,
a woman with just such damage had great
difficulty crossing the street. Although she
had no trouble recognizing cars (the what),
she could not tell where they were. She could
not even distinguish approaching cars from
parked cars (Zeki, 1991).
way
ath
)
lp
sa here
or
D (W
As you read this book, you may find yourself
wondering why psychologists are so interested in the brain. Brainwaves boxes like this
one are designed to help you think about
how the biopsychological perspective contributes to a better understanding of human
behavior.
Meet a woman we will call D. F., who suffered brain damage that caused severe visual
agnosia (Goodale et al., 1991). If D. F. was
shown an object, she could not recognize it.
Remarkably, even though she couldn’t recognize objects, D. F. could successfully manipulate them. For example, in one test she was
given a card and asked to insert it into a slot
at a certain angle. Although she could not
describe the slot’s orientation, she had no difficulty inserting the card into it. You could say
that D. F. displayed blindsight: When shown
an object, she was blind to what the object
T
(c)
4.11 Tests of visual acuity. Here are some common tests of visual acu•ity.Figure
In (a) sharpness is indicated by the smallest grating still seen as individual lines.
The Snellen chart (b) requires that you read rows of letters of diminishing size until
you can no longer distinguish them. The Landolt rings (c) require no familiarity with
letters. All that is required is a report of which side has a break in it.
rod vision is not very sharp, the rods are quite sensitive to movement in peripheral vision. To experience this characteristic of the
rods, look straight ahead and hold your hand beside your head, at
about 90 degrees. Wiggle your finger and slowly move your hand
forward until you can detect motion. You will become aware of the
movement before you can actually “see” your finger.
Seeing “out of the corner of the eye” is important for sports,
driving, and walking down dark alleys. People who suffer from
tunnel vision (a loss of peripheral vision) feel as if they are wearing
blinders (Godnig, 2003). Tunnel vision can also occur temporarily
when we are overloaded by a task. For example, if you were playing
a demanding video game you might be excused for not noticing
that a friend had walked up beside you.
Color Vision — There’s More
to It Than Meets the Eye
Gateway Question: How do we perceive colors?
What would you say is the brightest color? Red? Yellow? Blue?
Actually, there are two answers to this question, one for the rods and
one for the cones. The cones are most sensitive to the yellowish green
part of the spectrum. In other words, if all colors are tested in daylight (with each reflecting the same amount of light), then yellowish
green appears brightest. Yellow-green fire trucks and the bright yellow vests worn by roadside work crews are a reflection of this fact.
To what color are the rods most sensitive? Remember that the rods
do not produce color sensations. If you were looking at a very dim
colored light, you wouldn’t see any color. Even so, one light would
appear brighter than the others. When tested this way, the rods are
most sensitive to blue-green lights. Thus, at night or in dim light,
when rod vision prevails, the brightest-colored light will be one that
Visual acuity The sharpness of visual perception.
Fovea An area at the center of the retina containing only cones.
Peripheral vision Vision at the edges of the visual field.
128
CHAPTER 4
is blue or blue-green. For this reason, police and highway patrol cars
in many states now have blue emergency lights for night work. Also,
you may have wondered why the taxiway lights at airports are blue. It
seems like a poor choice, but blue is actually highly visible to pilots.
Color Theories
How do the cones produce color sensations? The trichromatic (TRYkro-MAT-ik) theory of color vision holds that there are three
types of cones, each most sensitive to either red, green, or blue.
Other colors result from combinations of these three.
A basic problem with the trichromatic theory is that four colors
of light — red, green, blue, and yellow — seem to be primary (you
can’t get them by mixing other colors). Also, why is it impossible to
have a reddish green or a yellowish blue? These problems led to the
development of a second view, known as the opponent-process
theory, which states that vision analyzes colors into “either-or”
messages (Goldstein, 2007). That is, the visual system can produce
messages for either red or green, yellow or blue, black or white.
Coding one color in a pair (red, for instance) seems to block the
opposite message (green) from coming through. As a result, a reddish green is impossible, but a yellowish red (orange) can occur.
According to opponent-process theory, fatigue caused by making
one response produces an afterimage of the opposite color as the
system recovers. Afterimages are visual sensations that persist after a
stimulus is removed—like seeing a spot after a flashbulb goes off. To
see an afterimage of the type predicted by opponent-process theory,
look at Figure 4.12 and follow the instructions there.
Which color theory is correct? Both! The three-color theory
applies to the retina, where three different types of cone have been
found. Each contains a different type of iodopsin (i-oh-DOP-sin),
a light-sensitive pigment that breaks down when struck by light.
This triggers action potentials and sends neural messages to the
brain. The three types of cones are most sensitive to red, green, or
blue. Other colors result from combinations of these three. (Black
and white sensations are produced by the rods, which contain a
•
chemical called rhodopsin (row-DOP-sin), another light-sensitive
visual pigment.) As predicted, each form of iodopsin is most sensitive to light in roughly the red, green, or blue region. The three
types of cones fire nerve impulses at different rates to produce
various color sensations ( Figure 4.13).
In contrast, the opponent-process theory better explains what
happens in optic pathways and the brain after information leaves
the eye. For example, some nerve cells in the brain are excited by
the color red and inhibited by the color green. So both theories are
“correct.” One explains what happens in the eye itself. The other
explains how colors are analyzed after messages leave the eye
(Gegenfurtner & Kiper, 2003).
•
Constructing Colors
The preceding explanations present a fairly mechanical view of how
colors are sensed. In reality, color experiences are more complex. For
example, the apparent color of an object is influenced by the colors
of other nearby objects. This effect is called simultaneous color
contrast. It occurs because brain cell activity in one area of the cerebral cortex can be altered by activity in nearby areas. Simultaneous
contrast can make it difficult to paint a picture or decorate a room.
If you add a new color to a canvas or a room, all the existing colors
will suddenly look different. Typically, each time a new color is
added, all the other colors must be adjusted ( Figure 4.14).
More striking than simultaneous contrast is the fact that color
experiences are actively constructed in the brain. The brain does not
simply receive prepackaged color messages. It must generate color
from the data it receives. As a result, it is possible to experience color
where none exists. (See Figure 4.15 for an example.) Indeed, all our
experiences are at least partially constructed from the information
surrounding us. (We’ll explore this idea further later in this chapter.)
•
•
Firing rates of cones
Color experienced
Blue
Green
Red
Yellow
Orange
Purple
White
•
Figure 4.12 Negative afterimages. Stare at the dot near the middle of the
flag for at least 30 seconds. Then look immediately at a plain sheet of white paper or
a white wall. You will see the American flag in its normal colors. Reduced sensitivity
to yellow, green, and black in the visual system, caused by prolonged staring, results
in the appearance of complementary colors. Project the afterimage of the flag on
other colored surfaces to get additional effects.
B
G
R
4.13 Firing rates of blue, green, and red cones in response to differ•entFigure
colors. The taller the colored bar, the higher the firing rates for that type of cone.
As you can see, colors are coded by differences in the activity of all three types of
cones in the normal eye. (Adapted from Goldstein, 2007.)
Sensation and Reality
129
(a)
(b)
4.14 Notice how different the gray-blue color looks when it is placed
•onFigure
different backgrounds. Unless you are looking at a large, solid block of color,
simultaneous contrast is constantly affecting your color experiences.
Michael Newman/PhotoEdit
(c)
4.15 On the left is a “star” made of red lines. On the right, the red lines
•areFigure
placed on top of longer black lines. Now, in addition to the red lines, you will
see a glowing red disk, with a clear border. Of course, no red disk is printed on this
page. No ink can be found between the red lines. The glowing red disk exists only in
your mind. (After Hoffman, 1999, p. 111.)
Color Blindness and Color Weakness
Do you know anyone who regularly draws hoots of laughter by
wearing clothes of wildly clashing colors? Or someone who sheepishly tries to avoid saying what color an object is? If so, you probably know someone who is color blind.
What is it like to be color blind? What causes color blindness? A
person who is color blind cannot perceive colors. It is as if the
world is a black-and-white movie. The color-blind person either
lacks cones or has cones that do not function normally (Deeb,
2004). Such total color blindness is rare. In color weakness, or
partial color blindness, a person can’t see certain colors. Approximately 8 percent of Caucasian males are red-green color blind (but
fewer Asian American, African American, and Native American
males, and less than 1 percent of women, are) (Delpero et al.,
2005). These people see both reds and greens as the same color,
usually a yellowish brown ( Figure 4.16). Another type of color
•
•
Figure 4.16 Color blindness and color weakness. (a) Photograph illustrates normal color vision. (b) Photograph is printed in blue and yellow and gives an impression
of what a red-green color-blind person sees. (c) Photograph simulates total color blindness. If you are totally color blind, all three photos will look nearly identical.
weakness, involving yellow and blue, is extremely rare (Hsia &
Graham, 1997). (See “Are You Color Blind?”)
Color blindness is caused by changes in the genes that control
red, green, and blue pigments in the cones. Red-green color weak-
Trichromatic theory Theory of color vision based on three cone types:
red, green, and blue.
Opponent-process theory Theory of color vision based on three
coding systems (red or green, yellow or blue, black or white).
Simultaneous color contrast Changes in perceived hue that occur
when a colored stimulus is displayed on backgrounds of various colors.
Color blindness A total inability to perceive colors.
Color weakness An inability to distinguish some colors.
130
CHAPTER 4
D ISC O VERIN G P S YCH OLOG Y
Are You Color Blind?
How can I tell if I am color blind? Surprisingly,
it is not as obvious as you might think; some
of us reach adulthood without knowing. The
Ishihara test is commonly used to measure
color blindness and weakness. In the test,
numbers and other designs made of dots
are placed on a background also made of
Figure 4.17 A replica of the
•Ishihara
test for color blindness.
•
dots ( Figure 4.17). The background and
the numbers are of different colors (red and
green, for example). A person who is color
blind sees only a jumble of dots. If you have
normal color vision you can detect the numbers or designs (Birch & McKeever, 1993;
Coren, Ward, & Enns, 2004). The chart below
• Figure 4.17 lists what people with normal
color vision and color blindness see. Because
this chart is just a replica, it is not a definitive
test of color blindness. Nevertheless, if you
can’t see all the embedded designs, you may
be color blind or color weak.
Sensation and Reality
ness is a recessive, sex-linked trait. That means it is carried on the
X, or female, chromosome. Women have two X chromosomes, so
if they receive only one defective color gene, they still have normal
vision. Color-weak men, however, have only one X chromosome,
so they can inherit the defect from their mothers (who usually
don’t display any color weakness).
How can color-blind individuals drive? Don’t they have trouble
with traffic lights? Red-green color-blind individuals have normal
vision for yellow and blue, so the main problem is telling red lights
from green. In practice, that’s not difficult. The red light is always
on top, and the green light is brighter than the red. Also, “red”
traffic signals have yellow light mixed in with the red and a “green”
light that is really blue-green.
Dark Adaptation — Let There Be Light!
Gateway Question: How do we adjust to the dark?
What happens when the eyes adjust to a dark room? Dark adaptation is the dramatic increase in retinal sensitivity to light that
occurs after a person enters the dark (Goldstein, 2007). Consider
walking into a theater. If you enter from a brightly lighted lobby,
you practically need to be led to your seat. After a short time,
however, you can see the entire room in detail (including the
couple kissing over in the corner). It takes about 30 to 35 minutes
of complete darkness to reach maximum visual sensitivity ( Figure 4.18). At that point, your eye will be 100,000 times more sensitive to light.
What causes dark adaptation? Remember that both rods and
cones contain light-sensitive visual pigments. When struck by light,
visual pigments bleach, or break down chemically. The afterimages
you have seen after looking at a flashbulb are a result of this bleaching. To restore light sensitivity, the visual pigments must recombine, which takes time. Night vision is due mainly to an increase in
rhodopsin, the rod pigment. When completely dark adapted, the
human eye is almost as sensitive to light as the eye of an owl.
Low
•
Sensitivity to light
Rods only
High
Cones only
0
5
10
15
20
25
Time in the dark (minutes)
30
As you might have noticed, a few seconds of exposure to bright
white light can completely wipe out dark adaptation. That’s why
you should be sure to avoid looking at oncoming headlights when
you are driving at night — especially the new bluish-white xenon
lights.
Under normal conditions, glare recovery takes about 20 seconds, plenty of time for an accident. After a few drinks, it may take
30 to 50 percent longer because alcohol dilates the pupils, allowing more light to enter. Note, too, that dark adaptation occurs
more slowly as we grow older. This is one reason why injuries
caused by falling in the dark become more common among the
elderly ( Jackson, Owsley, & McGwin, 1999).
Is there any way to speed up dark adaptation? The rods are insensitive to extremely red light. That’s why submarines, airplane cockpits, and ready rooms for fighter pilots are illuminated with red
light. In each case, people can move quickly into the dark without
having to adapt. Because the red light doesn’t stimulate the rods, it
is as if they had already spent time in the dark.
Can eating carrots really improve vision? One chemical “ingredient” of rhodopsin is retinal, which the body makes from vitamin
A. (Retinal is also called retinene.) When too little vitamin A is
available, less rhodopsin is produced. Thus, a person lacking vitamin A may develop night blindness. In night blindness, the person can see normally in bright light while using the cones, but
becomes blind at night when the rods must function. Carrots are
an excellent source of vitamin A, so they could improve night
vision for someone suffering a deficiency, but not the vision of
anyone with an adequate diet (Carlson, 2005).
KNOWL E DG E B U I L DE R
Vision
RECITE
1. The __________________ ___________________ is made up of
electromagnetic radiation with wavelengths between 400 and 700
nanometers.
2. Hyperopia is related to
a. farsightedness
b. having an elongated eye
c. corneal astigmatism
d. lack of cones in the fovea
3. Hubel and Wiesel found that cells in the visual cortex of the brain
function as ________________________ ______________________.
4. In dim light, vision depends mainly on the ____________________.
In brighter light, color and fine detail are produced by the
____________________.
5. The fovea has the greatest visual acuity due to the large concentration of rods found there. T or F?
6. The term “20/20 vision” means that a person can see at 20 feet what
can normally be seen from 20 feet. T or F?
Continued
Figure 4.18 Typical course of dark adaptation. The black line shows how the
•threshold
for vision lowers as a person spends time in the dark. (A lower threshold
means that less light is needed for vision.) The green line shows that the cones
adapt first, but they soon cease adding to light sensitivity. Rods, shown by the red
line, adapt more slowly. However, they continue to add to improved night vision
long after the cones are fully adapted.
131
Dark adaptation Increased retinal sensitivity to light.
Night blindness Blindness under conditions of low illumination.
132
CHAPTER 4
D ISC O VERIN G P S YCH OLOG Y
Felicia Rule
Going Biosonar
Although Ben Underwood has been blind since
the age of 3, he has learned to use echolocation
to do many things that normally sighted children
take for granted.
This chapter opened with a story about echolocation (also known as biosonar), the remarkable ability of bats to use the echoes of their
own voices to judge distance. Not human
at all, right? Don’t tell that to teenager Ben
Underwood, who has been sightless since
the age of 3, when retinal cancer claimed
his eyes (Engber, 2006). In 2006, Ben proudly
proclaimed during a television interview, “I’m
not blind, I just can’t see.” Sure enough, Ben
can ride a bike, climb trees, skate, and even
play video games. He does it by using echolocation.
It turns out that bat echolocation is especially powerful because bats use very highpitched sounds. But any sounds will do, and
Ben makes clicking sounds with his tongue.
With practice he has learned to use his
own echoes to navigate through the world.
Although Ben discovered echolocation all by
7. For the cones, the most visible color is
a. reddish orange
b. blue-green
c. yellow-orange
d. yellowish green
8. The eyes become more sensitive to light at night because
of a process known as ________________________
_________________________.
REFLECT
Critical Thinking
9. William James once said, “If a master surgeon were to cross the auditory and optic nerves, we would hear lightning and see thunder.”
Can you explain what James meant?
10. Sensory transduction in the eye takes place first in the cornea, then
in the lens, then in the retina. T or F?
Relate
Pretend you are a beam of light. What will happen to you at each step as
you pass into the eye and land on the retina? What will happen if the eye
is not perfectly shaped? How will the retina know you’ve arrived? How
will it tell what color of light you are? What will it tell the brain about you?
himself (!), it turns out that researchers have
known about human echolocation for 50
years and have even proposed training blind
people to echolocate (Kellogg, 1962).
Although blind people may be better at
echolocating, there is no reason why the rest
of us can’t do it as well (Rosenblum, Gordon,
& Jarquin, 2000). Try this: Blindfold yourself and have a friend move a large plate or
pan closer or farther away from you. All the
while, make some noise. Click like Ben does
or sing a song or whistle. Don’t expect to
hear your own echo as a separate sound.
Noticeable echoes only occur when sounds
bounce off objects far away. Instead, expect
to hear slight differences when an object
is moved. With some practice, you can tell
when the plate or pan is closer and when
it is farther away. Congratulations, you’ve
gone biosonar.
Hearing — Good Vibrations
Gateway Question: What are the mechanisms of hearing?
Rock, classical, jazz, rap, country, electronic, hip-hop — whatever
your musical taste, you have probably been moved by the riches of
sound. Hearing also collects information from all around the
body, such as detecting the approach of an unseen car (Yost,
2007). Vision, in all its glory, is limited to stimuli in front of the
eyes (unless, of course, your “shades” have rearview mirrors
attached).
Compression
Rarefaction
Amplitude
Compression
Wavelength
Rarefaction
Time
4.19 Waves of compression in the air, or vibrations, are the stimulus
•forFigure
hearing. The frequency of sound waves determines their pitch. The amplitude
determines loudness.
Answers: 1. visible spectrum 2. a 3. feature detectors 4. rods, cones 5. F
6. T 7. d 8. dark adaptation 9. The explanation is based on localization of
function: If a lightning flash caused rerouted messages from the eyes to
activate auditory areas of the brain, we would experience a sound sensation. Likewise, if the ears transduced a thunderclap and sent impulses
to the visual area, a sensation of light would occur. 10. False. The cornea
and lens bend and focus light rays, but they do not change light to
another form of energy. No change in the type of energy takes place until
the retina converts light to nerve impulses.
Sensation and Reality
External Ear
(air conduction)
Auditory
canal
133
•
Figure 4.20 Anatomy of the ear. The entire ear is a mechanism
for changing waves of air pressure into nerve impulses. The inset in
the foreground (Cochlea “Unrolled”) shows that as the stapes moves
the oval window, the round window bulges outward, allowing waves
to ripple through fluid in the cochlea. The waves move membranes
near the hair cells, causing cilia or “bristles” on the tips of the cells
to bend. The hair cells then generate nerve impulses carried to the
brain. (See an enlarged cross section of cochlea in Figure 4.21.)
Inner Ear
(fluid conduction)
(bone conduction
by ossicles)
Vestibular
apparatus
Incus
Malleus
Stapes
Auditory
nerve
•
Cochlea
Scala vestibuli
(with perilymph)
Pinna
Cochlear
canal (with
endolymph)
Round
window
Oval
window
Tympanic
membrane
(eardrum)
Stapes
Scala tympani
(with perilymph)
Cochlea in
Cross Section
Oval
window
waves collide with the tympanic membrane
(eardrum), setting it in motion. This, in turn,
Cochlear
causes three small bones (the auditory ossicles)
canal
(OSS-ih-kuls) to vibrate ( Figure 4.20).
The ossicles are the malleus (MAL-ee-us),
Perilymph
Round
Cochlea “Unrolled”
(fluid inside cochlea)
window
incus, and stapes (STAY-peas). Their common names are the hammer, anvil, and stirrup. The ossicles link the eardrum with the
What is the stimulus for hearing? If you throw
cochlea (KOCK-lee-ah: a snail-shaped organ
a stone into a quiet pond, a circle of waves will
that makes up the inner ear). The stapes is
spread in all directions. In much the same way,
attached to a membrane on the cochlea
Basilar
Auditory nerve
Hair cells
membrane
sound travels as a series of invisible waves of com- fibers
called the oval window. As the oval window
Organ of Corti
pression (peaks) and rarefaction (RARE-eh-fakmoves back and forth, it makes waves in a
shun: valleys) in the air. Any vibrating object — a
fluid inside the cochlea.
tuning fork, the string of a musical instrument, or the vocal
Inside the cochlea tiny hair cells detect waves in the fluid. The
cords — will produce sound waves (rhythmic movement of air
hair cells are part of the organ of Corti (KOR-tee), which makes
molecules). (To learn how to use sound waves to act like a bat, read
up the center part of the cochlea ( Figure 4.21). A set of stereocilia (STER-ee-oh-SIL-ih-ah), or “bristles,” atop each hair cell
“Going Biosonar.”) Other materials, such as fluids or solids, can
brush against the tectorial membrane when waves ripple through
also carry sound. But sound does not travel in a vacuum or the airfluid surrounding the organ of Corti. As the stereocilia are bent,
less realm of outer space. Movies that show characters reacting to
transduction takes place and nerve impulses are triggered, which
the “roar” of alien starships or titanic battles in deep space are in
then flow to the brain. (Are your ears “bristling” with sound?)
error.
The frequency of sound waves (the number of waves per secHow are higher and lower sounds detected? The frequency theond) corresponds to the perceived pitch (higher or lower tone) of
ory of hearing states that as pitch rises, nerve impulses of a correa sound. The amplitude, or physical “height,” of a sound wave tells
sponding frequency are fed into the auditory nerve. That is, an
how much energy it contains. Psychologically, amplitude corre800-hertz tone produces 800 nerve impulses per second. (Hertz
sponds to sensed loudness (sound intensity) ( Figure 4.19).
•
•
•
How We Hear Sounds
How are sounds converted to nerve impulses? Hearing involves an
elaborate chain of events that begins with the pinna (PIN-ah: the
visible, external part of the ear). In addition to being a good place to
hang earrings or balance pencils, the pinna acts like a funnel to concentrate sounds. After they are guided into the ear canal, sound
Hair cells Receptor cells within the cochlea that transduce vibrations
into nerve impulses.
Organ of Corti Center part of the cochlea, containing hair cells, canals,
and membranes.
Frequency theory Holds that tones up to 4,000 hertz are converted to
nerve impulses that match the frequency of each tone.
134
CHAPTER 4
Stereocilia
•
Dr. G. Oran Bredberg/SPL/Photo Researchers
Hair cells
Basilar membrane
Figure 4.21
A closer view of the hair cells shows how movement of fluid in
the cochlea causes the bristling “hairs” or cilia to bend, generating a nerve impulse.
Oval window
Stapes
Round
window
High frequency
Basilar
membrane
Medium frequency
Figure 4.23 A highly magnified electron microscope photo of the cilia
•(orange
bristles) on the top of human hair cells. (Colors are artificial.)
For example, the eardrums or ossicles may be damaged or immobilized by disease or injury. In many cases, conductive hearing loss
can be overcome with a hearing aid, which makes sounds louder
and clearer.
Sensorineural hearing loss results from damage to the inner
ear hair cells or auditory nerve. The hair cells, which are about as
thin as a cobweb, are very fragile ( Figure 4.23). By the time you
are 65, more than 40 percent of them will be gone, mainly those
that transduce high pitches (Chisolm, Willott, & Lister, 2003).
This explains why younger students are beginning to download
very high-pitched ring tones for their cell phones: If their teacher
has aging ears, the students can hear the ring tone while their
teacher cannot. (Your authors may have experienced this effect
without knowing it!)
Many jobs, hobbies, and pastimes can cause noise-induced
hearing loss, a common form of sensorineural hearing impairment that occurs when very loud sounds damage hair cells (as in
hunter’s notch). If you work in a noisy environment or enjoy loud
music, motorcycling, snowmobiling, hunting, or similar pursuits,
you are risking noise-induced hearing loss. Consider taking precautions because dead hair cells are never replaced: When you
abuse them, you lose them.
So sensorineural hearing loss cannot be treated? Not easily,
because hearing aids are of little or no help. However, in many
cases of sensorineural hearing loss, the auditory nerve is actually
intact. This finding has spurred the development of cochlear
implants that bypass hair cells and stimulate the auditory nerves
directly.
As you can see in Figure 4.24, wires from a microphone carry
electrical signals to an external coil. A matching coil under the skin
picks up the signals and carries them to one or more areas of the
cochlea. The latest implants make use of place theory to separate
higher and lower tones. This has allowed some formerly deaf persons to hear human voices, music, and other higher-frequency
sounds. About 60 percent of all multichannel implant patients can
understand some spoken words and appreciate music (Leal et al.,
2003; Tye-Murray, Spencer, & Woodworth, 1995). Some deaf
•
Low frequency
•
Figure 4.22 Here we see a simplified side view of the cochlea “unrolled.”
Remember that the basilar membrane is the elastic “roof” of the lower chamber of
the cochlea. The organ of Corti, with its sensitive hair cells, rests atop the basilar
membrane. The colored line shows where waves in the cochlear fluid cause the
greatest deflection of the basilar membrane. (The amount of movement is exaggerated in the drawing.) Hair cells respond most in the area of greatest movement,
which helps identify sound frequency.
refers to the number of vibrations per second.) This explains how
sounds up to about 4,000 hertz reach the brain. But what about
higher tones? Place theory states that higher and lower tones
excite specific areas of the cochlea. High tones register most
strongly at the base of the cochlea (near the oval window). Lower
tones, on the other hand, mostly move hair cells near the narrow
outer tip of the cochlea ( Figure 4.22). Pitch is signaled by the
area of the cochlea most strongly activated. Place theory also
explains why hunters sometimes lose hearing in a narrow pitch
range. “Hunter’s notch,” as it is called, occurs when hair cells are
damaged in the area affected by the pitch of gunfire.
•
Hearing Loss
What causes other types of hearing loss? The two most common
types of hearing loss afflict some 278 million people worldwide
(Tennesen, 2007). Conductive hearing loss occurs when the
transfer of vibrations from the outer ear to the inner ear is weak.
•
Sensation and Reality
Typical
Decibel Level
el
Skin
Internal coil
External
coil
Dangerous Time Exposure
180
Receiver
circuitry
135
Examples
Space Shuttle launch
170
160
Cochlea
Hearing loss certain
150
140
Eardrum
Electrode
to cochlea
Extremely loud 130
Any exposure dangerous
Immediate danger
80
70
Average automobile
110
Very loud
• Figure 4.24 A cochlear implant, or “artificial ear.”
Siren at 50 feet
Stereo headset (full volume)
Threshold of pain
Thunder, rock concert
Basketball or hockey crowd
Riveter
Factory noise, chain saw
Subway, tractor, power mower
Screaming child
Bus, motorcycle, snowmobile
Loud home stereo, food blender
Heavy traffic
120
To microphone and
sound processor
Shotgun blast
Jet airplane
100
90
Less than 8 hours
More than 8 hours
children learn to speak. Those who receive a cochlear
Normal conversation
60
implant before age 2 learn spoken language at a near norQuiet auto
50
Quiet
mal rate (Dorman & Wilson, 2004).
Quiet office
40
At present, artificial hearing remains crude. All but the
30
most successful cochlear implant patients describe the
Whisper at 5 feet
Very quiet
20
Broadcast studio when quiet
sound as “like a radio that isn’t quite tuned in.” In fact, 30
Studio for making sound pictures
10
percent of all adults who have tried implants have given
Just audible
up on them. But cochlear implants are improving. And
0
Figure 4.25 Loudness ratings and potential hearing damage.
even now it is hard to argue with enthusiasts like Kristen
Cloud. Shortly after Kristen received an implant, she was
able to hear a siren and avoid being struck by a speeding
car. She says simply, “The implant saved my life.”
How loud must a sound be to be hazardous? The danger of hearSmell and Taste — The Nose Knows
ing loss depends on both the loudness of sound and how long you
When the Tongue Can’t Tell
are exposed to it. Daily exposure to 85 decibels or more may cause
Gateway Question: How do the chemical senses operate?
permanent hearing loss (Sekuler & Blake, 2006). Even short periods at 120 decibels (a rock concert) may cause a temporary threshold
Unless you are a wine taster, a perfume blender, a chef, or a gourshift (a partial, transitory loss of hearing). Brief exposure to 150
met, you may think of olfaction (smell) and gustation (taste) as
decibels (a jet airplane nearby) can cause permanent hearing loss.
minor senses. Certainly you could survive without these two
You might find it interesting to check the decibel ratings of
chemical senses (receptors that respond to chemical molecules).
some of your activities in Figure 4.25. Don’t be fooled by the
But don’t be deceived. Life without these senses can be difficult
numbers, though. Decibels are plotted on a logarithmic scale (like
(Drummond, Douglas, & Olver, 2007). One person, for instance,
earthquake intensity!). Every 20 decibels increases the sound presalmost died because he couldn’t smell the smoke when his apartsure by a factor of 10. In other words, a rock concert at 120 deciment building caught fire. Without the chemical senses, people
bels is not just twice as powerful as a normal voice at 60 decibels.
may be unable to cook, may have difficulty maintaining a healthy
It is actually 1,000 times stronger. Be aware that amplified musical
body weight due to diminished appetites, and may even be poiconcerts, iPod-style headphones, and “boom-box” car stereos can
also damage your hearing.
If tinnitus (tin-NYE-tus: a ringing or buzzing sensation) folPlace theory Theory that higher and lower tones excite specific areas of
lows exposure to loud sounds, chances are that hair cells have been
the cochlea.
damaged. Almost everyone has tinnitus at times, especially with
Conductive hearing loss Poor transfer of sounds from the eardrum to
increasing age. But after repeated sounds that produce this warnthe inner ear.
ing, you can expect to become permanently hard-of-hearing. A
Sensorineural hearing loss Loss of hearing caused by damage to the
study of people who regularly go to amplified concerts found that
inner ear hair cells or auditory nerve.
44 percent had tinnitus and most had some hearing loss (MeyerNoise-induced hearing loss Damage caused by exposing the hair cells
Bisch, 1996).
to excessively loud sounds.
The next time you are exposed to a very loud sound, remember
Olfaction The sense of smell.
Figure 4.24 and take precautions against damage. (Remember,
too, that for temporary ear protection, fingers are always handy.)
Gustation The sense of taste.
•
•
•
CHAPTER 4
soned by spoiled food (Brisbois et al., 2006; Gilbert & Wysocki,
1987). Besides, olfaction and gustation add pleasure to our lives.
Skilled novelists always include descriptions of odors and tastes in
their writings because they are among the most memorable sensations. Perhaps authors intuitively realize that a scene is incomplete
without smells and tastes. Likewise, this chapter would be incomplete without a description of the chemical senses.
The Sense of Smell
Smell receptors respond to airborne molecules. As air enters the
nose, it flows over roughly 5 million nerve fibers embedded in
the lining of the upper nasal passages. Molecules passing over the
fibers trigger nerve signals that are sent to the brain. The extreme
close-up of an olfactory receptor cell in Figure 4.26c shows the
thread-like fibers that project into the air flow inside the nose.
Receptor proteins on the surface of the fibers are sensitive to various airborne molecules. When a fiber is stimulated, it sends signals
to the brain.
How are different odors produced? This is still an unfolding mystery. One hint comes from a type of dysosmia (dis-OZE-me-ah:
defective smell), a sort of “smell blindness” for a single odor. Loss
of sensitivity to specific types of odors suggests there are receptors
for specific odors. Indeed, the molecules that produce a particular
odor are quite similar in shape. Specific shapes produce the following types of odors: floral (flower-like), camphoric (camphor-like),
musky (have you ever smelled a sweaty musk ox?), minty (mintlike), and etherish (like ether or cleaning fluid).
Does this mean that there are five different types of olfactory receptors? Actually, in humans, about 1,000 types of smell receptors are
believed to exist (Bensafi et al., 2004). It appears that different-
•
Afferent fibers of
olfactory nerve
shaped “holes,” or “pockets,” exist on the surface of olfactory receptors. Like a piece fits in a puzzle, chemicals produce odors when
part of a molecule matches a hole of the same shape. This is the
lock and key theory of olfaction.
Further, molecules trigger activity in different combinations of
odor receptors. Thus, humans can detect at least 10,000 different
odors. Just as you can make many thousands of words from the 26
letters of the alphabet, many combinations of receptors are possible,
resulting in many different odors. Scents are also identified, in part,
by the location of the receptors in the nose that are activated by a
particular odor. And finally, the number of activated receptors tells the
brain how strong an odor is (Bensafi et al., 2004). The brain uses
these distinctive patterns of messages it gets from the olfactory
receptors to recognize particular scents (Laurent et al., 2001).
What causes dysosmia? Five people out of 100 experience some
degree of dysosmia (Bramerson et al., 2004). Risks include infections, allergies, and blows to the head (which may tear the olfactory nerves). Exposure to chemicals such as ammonia, photodeveloping solutions, and hairdressing potions can also cause
dysosmia. If you value your sense of smell, be careful what you
breathe (Drummond, Douglas, & Olver, 2007; Herz, 2001).
It might seem that various odors are inherently good or bad
smelling. But newborn infants show no signs to reacting more
strongly to “good” versus “bad” odors. The U.S. military once tried
to create a stink bomb that could be used for clearing people out
of an area. No matter how foul the smell, nothing could be found
that was universally repelling. It appears that likes and dislikes for
various scents are learned (Herz, 2001). For example, a person
who smelled roses for the first time at her mother’s funeral might
dislike the scent of roses. Or one who smelled a skunk for the first
time during a backyard birthday party might like the scent of
Olfactory bulb
Richard Costana, Discover Magazine, 1993
136
To cerebral cortex
Cribriform plate
of ethmoid bone
Olfactory nerve fibers
Basal cell
(c)
Supporting cell
Receptor cell (bipolar)
Cilia
Nasal cavity
(a)
Nasal mucous membrane
(b)
• Figure 4.26 Receptors for the sense of smell (olfaction). (a) Olfactory nerve fibers respond to gaseous molecules. Receptor cells are shown in cross section to the left.
(b) Olfactory receptors are located in the upper nasal cavity. (c) On the right, an extreme close-up of an olfactory receptor shows fibers that sense gaseous molecules of various shapes.
Sensation and Reality
skunk. If you don’t like the fetid, rotten odor of “ripe” cheeses, you
just grew up in the wrong culture!
Pheromones: A Special Scent?
Among mammals, pheromones (FAIR-oh-moans: airborne
chemical signals) greatly affect mating, sexual behavior, recognizing family members, and territorial marking (Kalat, 2007). For
example, when a female pig is exposed to the pheromones in a
male pig’s breath, she immediately becomes sexually receptive.
The vomeronasal (voh-MARE-oh-NAZE-ul) organ (VNO) is
the sense organ for pheromones. Until recently, humans were
assumed to have only a vestigial VNO or none at all. Now, however, scientists believe they have located the VNO in humans
(Hays, 2003). The suspected human vomeronasal organ looks like
a small pit inside the nose (one on each side of the septum). These
pits are lined with nerve cells and respond to chemicals that are
suspected pheromones (Benson, 2002).
Does this mean that someone could use pheromones to “turn on”
their girlfriend or boyfriend? It is doubtful that human pheromones
directly release sexual behavior. At best the effect would be indirect because pheromones are not smelled, felt, seen, tasted, or
heard. In humans, they appear to unconsciously produce general
moods, such as well-being, attraction, unease, or anxiety (Olsson
et al., 2006). When people say that their relationships are influenced by good or bad “chemistry,” there may be some truth to it.
Pheromones could add to the intoxicating feelings of romantic
attraction or the sourness of instant dislike.
In fact, one group of researchers believe that adding a pheromone to aftershave lotion can make men more sexually attractive
(McCoy & Pitino, 2002). (However, the most likely human
pheromones are found in underarm sweat, which is not exactly an
enticing thought.) Even then, social context appears to influence
the effect. For instance, the ability of pheromones to induce a
positive mood depends on whether a person of the opposite sex is
nearby ( Jacob, Hayreh, & McClintock, 2001).
Evidence for the existence of human pheromones remains preliminary and controversial. (Men shouldn’t expect “Boar’s Breath”
cologne to be offered anytime soon!) Nevertheless, the possibilities are intriguing (Ebster & Kirk-Smith, 2005). For instance,
human pheromones appear to explain why the menstrual cycles of
women who live together tend to become synchronized. It’s also
possible that pheromones may one day be used to decrease anxiety,
curb hunger, relieve premenstrual discomforts, or aid sex therapy.
Only further study will tell whether searching for these special
scents makes sense.
137
describes a pleasant savory or “brothy” taste associated with certain amino acids in chicken soup, some meat extracts, kelp, tuna,
human milk, cheese, and soybeans. The receptors for umami are
sensitive to glutamate, a substance found in monosodium glutamate (MSG) (Sugimoto & Ninomiya, 2005). Perhaps MSG’s
reputation as a “flavor enhancer” is based on the pleasant umami
taste (McCabe & Rolls, 2007). At the very least, we may finally
know why chicken soup is such a “comfort food.”
If there are only four or five tastes, how can there be so many different flavors? Flavors seem more varied because we tend to include
sensations of texture, temperature, smell, and even pain (“hot”
chili peppers) along with taste. Smell is particularly important in
determining flavor (Shepherd, 2006). If you plug your nose and
eat small bits of apple, potato, and onion, they will “taste” almost
exactly alike. So do gourmet jelly beans! It is probably fair to say
that subjective flavor is half smell. That’s why food loses its “taste”
when you have a cold.
Taste buds (taste-receptor cells) are mainly located on the top
side of the tongue, especially around the edges. However, a few are
found elsewhere inside the mouth ( Figure 4.27). As food is
chewed, it dissolves and enters the taste buds, where it sets off
nerve impulses to the brain (Northcutt, 2004). Much like smell,
sweet and bitter tastes appear to be based on a lock-and-key match
between molecules and intricately shaped receptors. Saltiness and
sourness, however, are triggered by a direct flow of charged atoms
into the tips of taste cells (Lindemann, 2001).
People seem to have very different tastes. Why is that? Some differences are genetic. The chemical phenylthiocarbamine (FEENil-thigh-oh-CAR-bah-meen), or PTC, tastes bitter to about 70
percent of those tested and has no taste for the other 30 percent.
Sensitivity to tastes has a genetic basis (Bartoshuk, 2000). In general, taste sensitivity is related to how many taste buds you have on
your tongue. Some people have as few as 500 taste buds, whereas
others have as many as 10,000. Those with many taste buds are
“supertasters” who need only half as much sugar in their coffee to
make it sweet (Bartoshuk et al., 2004).
Supertasters tend to have stronger tastes for sweet, bitter, and
irritants such as alcohol and capsaicin (the chemical that makes
chilies hot). Women are more often supertasters. Nontasters tend
to prefer sweets and fatty foods, which may be why supertasters
tend to be slimmer than nontasters.
The sense of taste also varies with age. Taste cells only live for
several days. With aging, cell replacement slows, so the sense of
taste diminishes. That’s why many foods you disliked in childhood
may seem appetizing now. Children who will not eat broccoli,
•
Taste and Flavors
There are at least four basic taste sensations: sweet, salt, sour, and
bitter. We are most sensitive to bitter, less sensitive to sour, even
less sensitive to salt, and least sensitive to sweet. This order may
have helped prevent poisonings when most humans foraged for
food, because bitter and sour foods are more likely to be inedible.
Most experts now believe that a fifth taste quality exists (Chandrashekar et al., 2006). The Japanese word umami (oo-MAH-me)
Dysosmia Loss or impairment of the sense of smell.
Lock and key theory of olfaction Holds that odors are related to the
shapes of chemical molecules.
Pheromone An airborne chemical signal.
Taste bud The receptor organ for taste.
138
CHAPTER 4
Circular papilla
Filamentous papilla
Omikron/Photo Researchers, Inc.
Taste
bud
Hairlike
ending
of taste
receptor
(a)
• Figure 4.27 Receptors for taste: (a) The
tongue is covered with small protrusions called
spinach, liver, and so on may be having a very different taste experience than an adult. Aside from this fact, however, most taste preferences are acquired. Would you eat the coagulated secretion of
the modified skin glands of a cow after it had undergone bacterial
decomposition? If you would, you are a cheese fancier!
K NOW LED G E B U I L D E R
Hearing, Smell, and Taste
RECITE
1. The frequency of a sound wave corresponds to how loud it is. T or F?
2. Which of the following is not a part of the cochlea?
a. ossicles
b. pinna
c. tympanic membrane
d. all of the above
3. Which of the following is not important for the transduction of
sound?
a. pinna
b. ossicles
c. phosphenes
d. oval window
e. hair cells
4. According to the place theory of hearing, higher tones register most
strongly near the base of the cochlea. T or F?
5. Sensorineural hearing loss occurs when the auditory ossicles are
damaged. T or F?
6. Daily exposure to sounds with a loudness of _______ decibels may
cause permanent hearing loss.
7. Cochlear implants have been used primarily to overcome
a. conductive hearing loss
b. hunter’s notch
c. sensorineural hearing loss
d. tinnitus
8. Olfaction appears to be at least partially explained by the
_____________ _____________ _____________ theory of
molecule shapes and receptor sites.
9. From the standpoint of survival, we are fortunate that we are
least sensitive to bitter tastes. T or F?
Sensory nerve
(c)
(d)
REFLECT
Critical Thinking
10. Why do you think your voice sounds so different when you hear a
tape recording of your speech?
11. Smell and hearing differ from vision in a way that may aid survival.
What is it?
Relate
Close your eyes and listen to the sounds around you. As you do, try to
mentally trace the events necessary to convert vibrations in the air into
the sounds you are hearing. Review the discussion of hearing if you leave
out any steps.
What is your favorite food odor? What is your favorite taste? Can you
explain how you are able to sense the aroma and taste of foods?
Answers: 1. F 2. d 3. c 4. T 5. F 6. 85 7. c 8. lock and key 9. F 10. The
answer lies in another question: How else might vibrations from the
voice reach the cochlea? Other people hear your voice only as it is carried
through the air. You hear not only that sound, but also vibrations conducted by the bones of your skull. 11. Both smell and hearing can detect
stimuli (including signals of approaching danger) around corners, behind
objects, and behind the head.
papillae. (b) Most taste buds are found around the
top edges of the tongue (shaded area). However,
some are located elsewhere, including under the
tongue. Stimulation of the central part of the tongue
(b)
causes no taste sensations. All four primary taste sensations
occur anywhere that taste buds exist. (c) An enlarged drawing shows that taste
buds are located near the base of papillae. (d) Detail of a taste bud. These receptors
also occur in other parts of the digestive system, such as the lining of the mouth.
The Somesthetic Senses — Flying
by the Seat of Your Pants
Gateway Question: What are the somesthetic senses?
A gymnast “flying” through a routine on the uneven bars may rely
as much on the somesthetic senses as on vision (soma means
“body”; esthetic means “feel”). Even the most routine activities,
such as walking, running, or passing a sobriety test, would be
impossible without somesthetic information from the body. You
would find it very difficult to move, stay upright, or even stay alive
without touch, pain, balance, and other bodily senses. They are an
essential part of our sensory world.
What are the somesthetic senses? Somesthetic sensitivity includes
the skin senses (touch), the kinesthetic senses (receptors in
Sensation and Reality
muscles and joints that detect body position and movement), and
the vestibular senses (receptors in the inner ear for balance, gravity, and acceleration). Let’s begin with the skin senses.
The Skin Senses
It’s difficult to imagine what life would be like without the sense of
touch, but the plight of Ian Waterman gives a hint. After an illness,
Waterman permanently lost all feeling below his neck. Now, in
order to know what position his body is in he has to be able to see
it. If he moves with his eyes closed, he has no idea where he is moving. If the lights go out in a room, he’s in big trouble (Cole,
1995).
Skin receptors produce at least five different sensations:
light touch, pressure, pain, cold, and warmth. Receptors with
particular shapes appear to specialize somewhat in various sensations ( Figure 4.28). However, free nerve endings alone can
produce all five sensations (Carlson, 2005). Altogether, the skin
has about 200,000 nerve endings for temperature, 500,000 for
touch and pressure, and 3 million for pain.
Does the number of receptors in an area of skin relate to its sensitivity? Yes. Your skin could be “mapped” by applying heat, cold,
touch, pressure, or pain to points all over your body. Such testing
would show that the number of skin receptors varies and that sensitivity generally matches the number of receptors in a given area.
As a rough-and-ready illustration, try this two-point touch test:
•
The density of touch receptors on various body areas can be checked by
having a friend apply two pencil points to the skin with varying distances
between them. Without looking, you should respond “one” or “two” each
time. Record the distance between the pencils each time you feel two
points.
139
You should find that two points are recognizable when they are
1/10 inch apart on the fingertips, 1/4 inch on the nose, and
3 inches at the middle of the back. Generally speaking, important
areas such as the lips, tongue, face, hands, and genitals have a
higher density of receptors. Of course, the sensation you ultimately feel will depend on brain activity.
Pain
The number of pain receptors also varies, right? Yes, like the other
skin senses, pain receptors vary in their distribution. About 230
pain points per square centimeter (about a half inch) are found
behind the knee, 180 per centimeter on the buttocks, 60 on the
pad of the thumb, and 40 on the tip of the nose. (Is it better, then,
to be pinched on the nose or behind the knee? It depends on what
you like!)
Pain fibers are also found in the internal organs. Stimulation of
these fibers causes visceral pain. Curiously, visceral pain is often
felt on the surface of the body, at a site some distance from the
point of origin. Experiences of this type are called referred pain
( Figure 4.29). For example, a person having a heart attack may
feel pain in the left shoulder, arm, or even the little finger.
Pain from the skin, muscles, joints, and tendons is known as
somatic (bodily) pain. Somatic pain carried by large nerve fibers is
sharp, bright, fast, and seems to come from specific body areas
(McMahon & Koltzenburg, 2005). This is the body’s warning system. Give yourself a small jab with a pin and you will feel this type
of pain. As you do this, notice that warning pain quickly disappears.
Much as we may dislike warning pain, it is usually a signal that the
body has been, or is about to be, damaged. Without warning pain,
we would be unable to detect or prevent injury. Children who are
born with a rare inherited insensitivity to pain repeatedly burn
themselves, break bones, bite off parts of their tongues, and become
ill without knowing it (Cox et al., 2006). As you might imagine, it’s
also hard for people with congenital pain insensitivity to have empathy for the pain of others (Danziger, Prkachin, & Willer, 2006).
•
Outer layer
of skin
Merkel’s disks
Free nerve
endings
Meissner
corpuscle’s
Krause’s
end-bulb
Nerve endings
around hair follicle
Pacinian
corpuscle
4.28 The skin senses include touch, pressure, pain, cold, and warmth.
•ThisFigure
drawing shows different forms the skin receptors can take. The only clearly specialized receptor is the Pacinian corpuscle, which is highly sensitive to pressure. Free
nerve endings are receptors for pain and any of the other sensations. For reasons
that are not clear, cold is sensed near the surface of the skin and warmth is sensed
deeper (Carlson, 2005).
Somesthetic sense Sensations produced by the skin, muscles, joints,
viscera, and organs of balance.
Skin senses The senses of touch, pressure, pain, heat, and cold.
Kinesthetic senses The senses of body movement and positioning.
Vestibular senses The senses of balance, position in space, and
acceleration.
Skin receptors Sensory organs for touch, pressure, pain, cold, and
warmth.
Visceral pain Pain originating in the internal organs.
Referred pain Pain that is felt in one part of the body but comes from
another.
Somatic pain Pain from the skin, muscles, joints, and tendons.
Warning system Pain based on large nerve fibers; warns that bodily
damage may be occurring.
140
CHAPTER 4
Liver and
gallbladder
Lung and
diaphragm
Heart
Pancreas
Small
intestine
Ovary
Appendix
Kidney
Stomach
Ovary
Colon
Urinary
bladder
Figure 4.30 Hold a variety of elongated objects upright between your
•fingertips.
Close your eyes and move each object about. Your ability to estimate
the size, length, shape, and orientation of each object will be quite accurate.
(After Turvey, 1996.)
• Figure 4.29 Visceral pain
often seems to come from the
surface of the body, even though
its true origin is internal. Referred
pain is believed to result from the
fact that pain fibers from internal
organs enter the spinal cord at the
same location as sensory fibers
from the skin. Apparently, the
brain misinterprets the visceral
pain messages as impulses from
the body’s surface.
Studies have shown that dynamic touch provides surprisingly
detailed information about objects, such as their size and shape
( Figure 4.30). How are we able to make such judgments? Psychologist M. T. Turvey has found that most bodily motions form
an arc or a combination of arcs (Turvey, 1996). Dynamic touch is
largely a matter of sensing the inertia of objects as they move
through these arcs. The fact that dynamic touch is a reliable
source of information is what makes it possible for us to use a
wide range of tools, utensils, and objects as if they were extensions
of our bodies (Hove, Riley, & Shockley, 2006).
•
The Vestibular System
A second type of somatic pain is carried by small nerve fibers.
This type is slower, nagging, aching, widespread, and very unpleasant (McMahon & Koltzenburg, 2005). It gets worse if the pain
stimulus is repeated. This is the body’s reminding system. It
reminds the brain that the body has been injured. For instance,
lower back pain often has this quality. Sadly, the reminding system
can cause agony long after an injury has healed, or in terminal illnesses, when the reminder is useless. This chapter’s Psychology in
Action section describes some ways to control pain. If you got carried away with the earlier pin demonstration, maybe you should
read ahead now!
Dynamic Touch
A carpenter swings a hammer with practiced precision. A juggler
fluidly tosses and catches five balls. An ice hockey player embeds
his stick in an opposing player’s helmet. In sports and everyday life,
touch is rarely static. Most skilled performances rely on dynamic
touch, which combines sensations from skin receptors with kinesthetic information from the muscles and tendons.
Space flight might look like fun. But if you ever get a ride into space,
it is about 70 percent likely that your first experience in orbit will be
throwing up. Weightlessness and space flight affect the vestibular
system, often causing severe motion sickness ( Figure 4.31). Within
the vestibular system, fluid-filled sacs called otolith (OH-toe-lith)
organs are sensitive to movement, acceleration, and gravity. The
otolith organs contain tiny crystals in a soft, gelatin-like mass. The
tug of gravity or rapid head movements can cause the mass to shift.
This, in turn, stimulates hair-like receptor cells, allowing us to sense
gravity, acceleration, and movement through space (Lackner &
DiZio, 2005).
Three fluid-filled tubes called the semicircular canals are the
sensory organs for balance. If you could climb inside these tubes,
you would find that head movements cause the fluid to swirl
about. As the fluid moves, it bends a small “flap,” or “float,” called
the crista, that detects movement in the semicircular canals. A
crista can be found within each ampulla (am-PULL-ah), a wider
part of the canal. The bending of each crista again stimulates hair
cells and signals head rotation.
•
141
Sensation and Reality
Inner Ear
Ampulla Enlarged
and Opened
Crista
Fluid
Semicircular canals
Nerve fibers
Ampullae
JSC/NASA
Figure 4.31 The vestibular
•system.
(See text for explanation.)
Otolith
organs
Cochlea
Weightlessness presents astronauts with a real challenge in sensory adaptation.
Why would sensory conflict cause nausea? You can probably
blame (or thank) evolution. Many poisons disturb the vestibular
system, vision, and the body. Therefore, we may have evolved so
that we react to sensory conflict by vomiting to expel poison. The
value of this reaction, however, may be of little comfort to anyone
who has ever been “green” and miserable with motion sickness.
In space, sensory conflict can be especially intense. During
weightlessness, merely pulling on one’s shoes can result in a backward somersault. Under such conditions, the otolith organs send
unexpected signals to the brain, and head movements are no longer confirmed by the semicircular canals. Few of the messages the
brain receives from the vestibular system and kinesthetic receptors
agree with a lifetime of past experience.
What can be done to minimize motion sickness? Whether you are
in outer space, playing a particularly intense video game, or just sitting in the backseat of a moving car, motion sickness is a very
unpleasant experience. If you face motion sickness, there are a few
things you can try that should help (Harm, 2002). If you know
beforehand that you might be at risk, consider taking nonprescription motion sickness pills. If you are trapped in the moment, try
Jiang Jin/SuperStock
What causes motion sickness? According to sensory conflict
theory, dizziness and nausea occur when sensations from the vestibular system don’t match sensations from the eyes and body
(Flanagan, May, & Dobie, 2004). On solid ground, information
from the vestibular system, vision, and kinesthesis usually matches.
However, in a heaving, pitching boat, car, or airplane, a serious
mismatch can occur — causing disorientation and heaving of
another kind.
Many people become nauseated the first time they experience virtual reality.
Why? Because virtual reality also creates a sensory conflict: Computer-generated
visual images change as if the viewer’s body is in motion, but the vestibular system tells viewers that they are standing still (Merhi et al., 2007). The result? The
scenery may not be real but the nausea is.
Reminding system Pain based on small nerve fibers; reminds the brain
that the body has been injured.
Dynamic touch Touch experienced when the body is in motion; a
combination of sensations from skin receptors, muscles, and joints.
Sensory conflict theory Explains motion sickness as the result of a
mismatch between information from vision, the vestibular system, and
kinesthesis.
142
CHAPTER 4
minimizing sensory conflict by moving your head as little as possible. Either close your eyes, fixate on an unmoving point (such as the
horizon), or look above the horizon at the unmoving sky. Also, lie
down if you can. The otoliths are less sensitive to vertical movements when you are horizontal, and your head will move less.
Finally, anxiety intensifies motion sickness. Try slow, deep breathing
and other relaxation techniques that you can use when needed.
Image projected
on screen
Slide containing “F”
Projector
lens
Slide projector
Retinal
image
Contact lens
(a)
bridges
Relaxation methods are described in Chapter 15 of this book.
Adaptation, Attention, and Gating —
Tuning In and Tuning Out
Gateway Question: Why are we more aware of some sensations than
others?
You are surrounded by sights, sounds, odors, tastes, and touch
sensations. Which are you aware of ? Each of the senses we have
described is continuously active. Even so, many sensory events
never reach awareness because of sensory adaptation, selective attention, and sensory gating. Let’s see how information is filtered by
these processes.
Sensory Adaptation
Think about walking into a house where fried fish, sauerkraut, and
head cheese were prepared for dinner. (Some dinner!) You would
probably pass out at the door, yet people who had been in the
house for some time wouldn’t be aware of the food odors. Similarly, smokers often don’t get how much nonsmokers are bothered
by the smell of tobacco smoke. Why? Because sensory receptors
respond less to unchanging stimuli, a process called sensory adaptation.
Fortunately, the olfactory (smell) receptors adapt quickly.
When exposed to a constant odor, they send fewer and fewer
nerve impulses to the brain until the odor is no longer noticed.
Adaptation to pressure from a wristwatch, waistband, ring, or
glasses is based on the same principle. Sensory receptors generally
respond best to changes in stimulation. No one wants or needs to
be reminded 16 hours a day that his shoes are on.
If change is necessary to prevent sensory adaptation, why doesn’t
vision undergo adaptation like the sense of smell does? If you stare at
something, it certainly doesn’t go away. The rods and cones, like
other receptor cells, would respond less to a constant stimulus.
However, the eye normally makes thousands of tiny movements
every minute. These movements are caused by physiological nystagmus (nis-TAG-mus: involuntary tremors of the eye muscles).
Although they are too small to be seen, the movements shift visual
images from one receptor cell to another.
Constant eye movement ensures that images always fall on
fresh, unfatigued rods and cones. Evidence for this comes from
(b)
Figure 4.32 Stabilized images. (a) A miniature slide projector attached to a
•contact
lens moves each time the eye moves. As a result, the projected image disappears in a few seconds because it does not move on the retina. (b) A similar effect
occurs when changes in brightness do not define a distinct edge. In this case, eye
movements cannot prevent adaptation. Therefore, if you stare at the dot, the lighter
area will disappear. (After Cornsweet, 1970.)
fitting people with a contact lens that has a miniature slide projector attached to it ( Figure 4.32a). Because the projector follows
the exact movements of the eye, an image can be stabilized on the
retina. When this is done, projected geometric designs fade from
view within a few seconds (Pritchard, 1961). You can get a similar
effect by staring at Figure 4.32b. Because the lighter circle does
not form a distinct edge, the retina adapts to the brightness difference. As it does, the circle gradually disappears.
•
•
Selective Attention
As you sit reading this page, receptors for touch and pressure in
the seat of your pants are sending nerve impulses to your brain.
Although these sensations have been present all along, you were
probably not aware of them until just now. This “seat-of-the-pants
phenomenon” is an example of selective attention (voluntarily
focusing on a specific sensory input). We are able to “tune in on” a
single sensory message while excluding others. Another familiar
example of this is the “cocktail party effect.” When you are in a
Sensation and Reality
group of people, surrounded by voices, you can still select and
attend to the voice of the person you are facing. Or if that person
gets dull, you can eavesdrop on conversations all over the room.
(Be sure to smile and nod your head occasionally!) Actually, no
matter how interesting your companion may be, your attention
will probably shift away if you hear your own name spoken somewhere in the room (Conway, Cowan, & Bunting, 2001). We do
find what others say about us to be very interesting, don’t we?
Sensory Gating
What makes selective attention possible? Selective attention appears
to be based on the ability of brain structures to select and divert
incoming sensory messages (Sekuler & Blake, 2006). But what
about messages that haven’t reached the brain? Is it possible that
some are blocked while others are allowed to pass? Evidence suggests there are sensory gates that control the flow of incoming nerve
impulses in just this way. In particular, sensory gating refers to
facilitating or blocking sensory messages in the spinal cord (Melzack & Katz, 2004; Melzack & Wall, 1996).
Pain Gates
A fascinating example of sensory gating is provided by Ronald
Melzack and Patrick Wall (1996), who study “pain gates” in the
spinal cord. Melzack and Wall noticed, as you may have, that one
type of pain will sometimes cancel another. Their gate control
theory suggests that pain messages from different nerve fibers pass
through the same neural “gate” in the spinal cord. If the gate is
“closed” by one pain message, other messages may not be able to
pass through (Melzack & Katz, 2004; Melzack & Wall, 1996).
How is the gate closed? Messages carried by large, fast nerve
fibers seem to close the spinal pain gate directly. Doing so can
prevent slower, “reminding system” pain from reaching the brain.
Pain clinics use this effect by applying a mild electrical current to
the skin. Such stimulation, felt only as a mild tingling, can greatly
reduce more agonizing pain.
Messages from small, slow fibers seem to take a different route.
After going through the pain gate, they pass on to a “central biasing system” in the brain. Under some circumstances, the brain
then sends a message back down the spinal cord, closing the pain
gates ( Figure 4.33). Melzack and Wall believe that gate control
theory explains the painkilling effects of acupuncture.
Acupuncture is the Chinese medical art of relieving pain and
illness by inserting thin needles into the body. As the acupuncturist’s needles are twirled, heated, or electrified, they activate small
pain fibers. These relay through the biasing system to close the
gates to intense or chronic pain (Melzack & Wall, 1996). Studies
have shown that acupuncture produces short-term pain relief for
40 to 80 percent of patients tested (Ernst, 1994; Weidenhammer
et al., 2007).
Acupuncture has an interesting side effect not predicted by
sensory gating. People given acupuncture often report feelings of
light-headedness, relaxation, or euphoria. How are these feelings
explained? The answer seems to lie in the body’s ability to pro-
•
143
4.33 Diagram of a sensory
•gateFigure
for pain. A series of pain impulses
going through the gate may prevent
other pain messages from passing
through. Or pain messages may
relay through a “central biasing
mechanism” that exerts control
over the gate, closing it to
other impulses.
Pain
sensation
Central biasing
mechanism
Spinal cord
Brainstem
Sensory gate
Small nerve
fibers
Large nerve
fibers
duce opiate-like chemicals. To combat pain, the brain causes the
pituitary gland to release a painkilling chemical called betaendorphin (BAY-tah-en-DOR-fin: from endo, “within,” and
orphin, “opiate”). Chemically, beta-endorphin is quite similar to
morphine.
Such discoveries help explain the painkilling effect of placebos
(fake pills or injections), which raise endorphin levels. A release of
endorphins also seems to underlie “runner’s high,” masochism,
acupuncture, and the euphoria sometimes associated with childbirth, painful initiation rites, or eating hot chili peppers (Kalat,
2007; Sternberg et al., 1998). In each case, pain and stress cause the
release of endorphins. These in turn induce feelings of pleasure or
euphoria similar to being “high” on morphine.
The “high” often felt by long-distance runners serves as a good
example of the endorphin effect. In one experiment, subjects were
tested for pain tolerance. After running 1 mile, each was tested
again. In the second test, all could withstand pain about 70 percent longer than before. The runners were then given naloxone, a
drug that blocks the effects of endorphins. Following another
1-mile run the subjects were tested again. This time they had lost
their earlier protection from pain (Haier et al., 1988). A similar
effect occurs with first-time parachute jumpers. After the jump,
their endorphin levels increase dramatically and they are much less
sensitive to pain ( Janssen & Arntz, 2001). Actually, these observa-
Sensory adaptation A decrease in sensory response to an unchanging
stimulus.
Selective attention Voluntarily focusing on a specific sensory input.
Sensory gating Alteration of sensory messages in the spinal cord.
Gate control theory Proposes that pain messages pass through neural
“gates” in the spinal cord.
Beta-endorphin A natural, painkilling brain chemical similar to
morphine.
144
CHAPTER 4
Herve Donnezan/Photo Researchers, Inc.
(left) An acupuncturist’s chart. (right) Thin stainless steel needles
are inserted into areas defined by the chart. Modern research has
begun to explain the painkilling effects of acupuncture (see text).
Acupuncture’s claimed ability to cure diseases is more debatable.
tions tie in nicely with the idea of pain gates. The central biasing
system, which closes pain gates in the spinal cord, is highly sensitive to morphine and other opiate painkillers (Kalat, 2007; Melzack & Wall, 1996). People who say they are “addicted” to running, or bungee jumping, or eating spicy foods may be closer to the
truth than they realize. (Can pain gates and endorphins explain
every type of pain? See “The Matrix: Do Phantoms Live Here?”)
Conclusion and a Look Ahead
The senses supply raw data to the brain, but the information
remains mostly meaningless until it is interpreted. It’s as if the
senses provide only the jumbled pieces of a complex puzzle. In the
next chapter we will explore some perceptual processes that help
us put the puzzle together.
A variety of psychological factors affect the severity of pain.
Because you may not want to try acupuncture or electrical stimulation to control everyday pain, the following discussion describes
several practical ways to reduce pain. Before we turn to that useful
topic, here’s a chance to rehearse what you’ve learned.
K NOW LED GE B U I L D E R
Somesthetic Senses, Adaptation,
Attention, and Gating
6. Sensory conflict theory appears to explain space sickness, but it
does not seem to apply to other types of motion sickness. T or F?
7. Sensory adaptation refers to an increase in sensory response that
accompanies a constant or unchanging stimulus. T or F?
8. The brain-centered ability to influence what sensations we will
receive is called
a. sensory gating
b. central adaptation
c. selective attention
d. sensory biasing
9. The painkilling effects of acupuncture appear to result from
__________________ _______________ and the release of betaendorphin.
REFLECT
Critical Thinking
10. What special precautions would you have to take to test the ability
of acupuncture to reduce pain?
11. In a very real sense, we all live slightly in the past. How could that be
true?
Relate
Stand on one foot with your eyes closed. Now touch the tip of your nose
with your index finger. Which of the somesthetic senses did you use to
perform this feat?
Imagine you are on a boat ride with a friend who starts to feel queasy.
Can you explain to your friend what causes motion sickness and what she
or he can do to prevent it?
As you sit reading this book, which sensory inputs have undergone
adaptation? What new inputs can you become aware of by shifting your
focus of attention?
RECITE
Answers: 1. d 2. T 3. large 4. dynamic touch 5. T 6. F 7. F 8. c 9. sensory
gating 10. At the very least, you would have to control for the placebo
effect by giving fake acupuncture to control group members. However,
a true double-blind study would be difficult to do. Acupuncturists would
always know if they were giving a placebo treatment or the real thing,
which means they might unconsciously influence subjects. 11. For all the
senses, it takes a split second for sensory receptors to sense a change in
external stimuli and for a neural message to arrive at the brain. Therefore,
by the time we are aware of an event, such as a very brief flash of light, it
is already over.
1. Which of the following is a somesthetic sense?
a. gestation
b. olfaction
c. rarefaction
d. kinesthesis
2. Pain that originates in the internal organs is sometimes felt on the
surface of the body as “referred pain.” T or F?
3. Warning pain is carried by ______________ nerve fibers.
4. An ability to sense the inertia of objects as we move them
through space is the basis for __________________________
_______________________.
5. Head movements are detected primarily in the semicircular canals,
gravity by the otolith organs. T or F?
Sensation and Reality
145
B RAIN W AVES
The Matrix: Do Phantoms Live Here?
In the popular Matrix films, Neo, as played by
Keanu Reeves, discovers that machines have
imprisoned humans in a phantom world
called the Matrix, in order to steal human
energy for their own use. Actually, the idea of
a “matrix” is not totally farfetched. In fact, your
own brain may be creating a neuromatrix that
allows you to perceive your own body.
A person who suffers an amputation
doesn’t need to believe in the Matrix to
encounter phantoms. Most amputees have
phantom limb sensations, including pain,
for months or years after losing a limb (Fraser,
2002; Halbert, Crotty, & Cameron, 2002).
Because the phantom limb feels so “real,” a
patient with a recently amputated leg may
inadvertently try to walk on it, risking further injury. Sometimes, phantom limbs feel
like they are stuck in awkward positions. For
instance, one man can’t sleep on his back
because his missing arm feels like it is twisted
behind him.
What causes phantom limbs? Gate control
theory cannot explain phantom limb pain
(Hunter, Katz, & Davis, 2003). Because pain
can’t be coming from the missing limb, it
cannot pass through pain gates to the brain
(after all, it’s missing!). Instead, according to
Ronald Melzack (1999; Melzack & Katz, 2006),
the brain creates a body image called the
neuromatrix. This internal model of the body
generates our sense of bodily self. Although
amputation may remove a limb, as far as the
neuromatrix in the brain is concerned, the
limb still exists. Functional magnetic resonance imaging (fMRI) confirms that sensory
and motor areas of the brain are more active
when a person feels a phantom limb (Rosen
et al., 2001). Even though pain signals no longer come from the amputated limb, the neuromatrix evidently interprets other sensory
experiences as pain from the missing limb.
Sometimes the brain gradually reorganizes to adjust for the sensory loss (Wu &
Kaas, 2002). For example, a person who loses
an arm may at first have a phantom arm and
hand. After many years, the phantom may
shrink, until only a hand is felt at the shoulder. Perhaps more vividly than others, people
with phantom limbs are reminded that the
sensory world we experience is constructed,
moment-by-moment, not by some futuristic
machines but by our very own neuromatrix
in our brains.
PSYC HOL O GY IN A CT ION
Controlling Pain — This Won’t Hurt a Bit
In some cultures, people endure tattooing,
stretching, cutting, and burning with little
apparent pain. How do they do it? Very likely
the answer lies in a reliance on psychological
factors that anyone can use to reduce pain,
such as anxiety reduction, control, attention,
and interpretation (Mailis-Gagnon & Israelson, 2005).
Gateway Question: How can pain be reduced
in everyday situations?
Steve Raymer/National Geographic/Getty Images
Anxiety
The basic sensory message of pain can be separated from emotional reactions to it. Fear or
high levels of anxiety almost always increase
pain. (Anxiety is a feeling of apprehension or
uneasiness similar to fear, but based on an
unclear threat.) A dramatic reversal of this
effect is the surprising lack of pain displayed by
soldiers wounded in battle. Being excused from
further combat apparently produces a flood of
relief. This emotional state leaves many soldiers insensitive to wounds that would agonize
a civilian (Melzack & Wall, 1996). In general,
unpleasant emotions increase pain and pleasant emotions decrease it (Rainville, 2004).
Control
A moment’s reflection should convince you
that the most upsetting pain is that over
which you have no control. Loss of control
seems to increase pain by increasing anxiety
and emotional distress. Conversely, if you can
regulate a painful stimulus, you have control
over it. People who are allowed to regulate,
avoid, or control a painful stimulus suffer less.
In general, the more control you feel you have
over a painful stimulus, the less pain you will
experience. (Vallerand, Saunders, & Anthony,
2007). To apply this principle, you should
arrange a signal so your doctor, dentist, or
Phantom limb The illusory sensation that a
limb still exists after it is lost through accident
or amputation.
Anxiety Apprehension, dread, or uneasiness
similar to fear but based on an unclear threat.
Control Where pain is concerned, control
refers to an ability to regulate the pain
stimulus.
CHAPTER 4
body piercer will know when to start and
stop a painful procedure.
Attention
Distraction can also radically reduce pain. As
you’ll recall, attention refers to voluntarily
focusing on a specific sensory input. Pain,
even though it is highly persistent, can be
selectively “tuned out” (at least partially), just
like any other sensation. Children in one
experiment tolerated pain better when they
were distracted by interacting with a headmounted audiovisual display (Dahlquist et
al., 2007). Similarly, burn patients, who must
undergo excruciating pain while their bandages are changed, can be distracted from
their pain with video games and virtual reality (Hoffman et al., 2001).
Less dramatically, have you ever temporarily forgotten about a toothache or similar
pain while absorbed in a movie or book? As
this suggests, concentrating on pleasant,
soothing images can be especially helpful.
Instead of listening to the whir of a dentist’s
drill, for example, you might imagine that
you are lying in the sun on a beach, listening
to the roar of the surf. Or take an iPod along
and crank up your favorite MP3s (Bushnell,
Villemure, & Duncan, 2004). At home, music
can also be a good distractor from chronic
pain (Mitchell et al., 2007).
Interpretation
The meaning, or interpretation, you give a
stimulus also affects pain (Turk & Melzack,
2001). For example, if you give a child a swat
on the behind while playing, you’ll probably
get a burst of laughter. Yet the same swat given
as punishment may bring tears. The effects of
interpretation are illustrated by a classic experiment in which thinking of pain as pleasurable
(denying the pain) greatly increased pain tolerance (Neufeld, 1970). Another study found
that people who believe a painful procedure
will improve their health feel less pain during
the procedure (Staats et al., 1998).
Coping with Pain
How can these facts be applied? In a sense,
they already are applied to childbirth. Prepared childbirth training, which promotes
birth with a minimum of drugs or painkillers, uses all four factors. To prepare for natural childbirth, the expectant mother learns in
great detail what to anticipate at each stage
of labor. This greatly relieves her fears and
anxieties. During labor, she attends to sensations that mark her progress and she adjusts
her breathing accordingly. Her attention is
shifted to sensations other than pain, resulting in less discomfort (Leventhal et al., 1989).
Also, her positive attitude is maintained by
use of the term “contractions” rather than
“labor pains.” Finally, because of her months
of preparation and her active participation,
she feels in control of the situation.
Natural childbirth techniques reduce pain
by an average of about 30 percent. Many
women find this reduction quite helpful.
However, it is important to remember that
labor can produce very severe pain. A woman
should not feel guilty if she needs painkillers
during labor. Many women who have had
prepared childbirth training still end up asking for an epidural block.
For moderate pain, it can make quite a
difference to reduce anxiety, redirect attention, and increase control. When you anticipate pain (during a trip to the doctor, dentist, or tattoo parlor), you can lower anxiety
by making sure that you are fully informed.
Be sure that someone explains everything
that will happen or could happen to you.
Also, be sure to fully discuss any fears you
have. If you are physically tense, you can use
relaxation exercises to lower your level of
arousal. Relaxation methods involve tensing
and then releasing muscles in various parts
of the body.
bridges
A typical technique is described
in detail in the Psychology in
Action section of Chapter 15. The
desensitization procedure described
there may also help reduce anxiety.
Distraction and Reinterpretation
Some dentists are now equipped to help you
shift attention away from pain. Patients are
actively distracted with video games and
headphones playing music. In other situations, focusing on some external object may
help you shift attention away from pain.
Pick a tree outside a window, a design on
the wall, or some other stimulus and examine it in great detail. Prior practice in meditation can be a tremendous aid to such
attention shifts. Research suggests that dis-
Dr. Anna Kalmanovich, Boxborough MA/todaysdentalob.com
146
New technologies like this audiovisual headset offer
new ways of distracting attention from painful experiences such as visits to the dentist.
traction of this type works best for mild or
brief pain. For chronic or strong pain, reinterpretation is more effective (McCaul &
Malott, 1984).
Counterirritation
Is there any way to increase control over a
painful stimulus? Practically speaking, the
choices may be limited. One possibility is
related to Ronald Melzack’s gate control theory of pain, which suggests that sending mild
pain messages to the spinal cord and brain
may effectively close the neurological gates to
more severe or unpredictable pain. Such procedures, known as counterirritation, are evident in some of the oldest techniques used to
control pain: applying ice packs, hot-water
bottles, mustard packs, vibration, or massage
to other parts of the body. Pain clinics use
counterirritation by applying a mild electrical
current to the skin. This causes only a mild
tingling, but it can greatly reduce more agonizing pain (Köke et al., 2004). For more
extreme pain, the electrical current can be
applied directly to the spinal cord (Linderoth
& Foreman, 2006).
These facts suggest a way to minimize
pain that is based on increased control, counterirritation, and the release of endorphins. If
Sensation and Reality
This fact can be used to mask one pain
with a second painful stimulus that is under
your control. For instance, if you are having a
tooth filled, try pinching yourself or digging a
fingernail into a knuckle while the dentist is
working. Focus your attention on the pain
K N O WL E D GE B U I L D E R
Pain Control
RECITE
1. Like heightened anxiety, increased control tends to increase subjective pain. T or F?
2. In one experiment, participants given the task of interacting
with a head-mounted audiovisual display experienced less
pain than participants who paid attention to the pain stimulus.
T or F?
3. Imagining a pleasant experience can be an effective way of reducing
pain in some situations. T or F?
4. The concept of counterirritation holds that relaxation and desensitization are key elements of pain control. T or F?
chapter in review
The senses act as data reduction systems in order to prevent the brain
from being overwhelmed by sensory input.
• Private sensations do not correspond perfectly to external
stimuli. Studies in psychophysics relate physical energies to the
sensations we experience.
• The sensory organs transduce a limited range of physical energies into nerve impulses.
• The minimum amount of physical energy necessary to produce a sensation defines the absolute threshold. The amount
of change necessary to produce a just noticeable difference in a
stimulus defines a difference threshold.
• There is evidence that subliminal perception occurs, but subliminal advertising is largely ineffective.
• Sensory analysis and coding influence what we experience.
• Sensory processing is localized in specific parts of the brain.
The visible spectrum is transduced by rods and cones in the retina
leading to the construction of visual experience by the brain.
• The visible spectrum consists of electromagnetic radiation in a
narrow range.
• The eyes and the brain form a complex system for sensing
light. Vision is based on an active, computer-like analysis of
light patterns.
• Four common visual defects are myopia (nearsightedness),
hyperopia (farsightedness), presbyopia (loss of accommodation), and astigmatism.
you are creating, and increase its intensity
anytime the dentist’s work becomes more
painful. This strategy may seem strange, but
it works. Generations of children have used it
to take the edge off a spanking.
REFLECT
Critical Thinking
5. What measures would you take to ensure that an experiment involving pain is ethical?
Relate
Think about a strategy you have used for reducing pain at the doctor,
dentist, or some other painful situation. Did you alter anxiety, control,
attention, or interpretation? Can you think of any ways in which you have
used counterirritation to lessen pain?
Answers: 1. F 2. T 3. T 4. F 5. Experiments that cause pain must be
handled with care and sensitivity. Participation must be voluntary, the
source of pain must be noninjurious, and subjects must be allowed to
quit at any time.
you pinch yourself, you can easily create and
endure pain equal to that produced by many
medical procedures (receiving an injection,
having a tooth drilled, and so on). The pain
doesn’t seem too bad because you have control over it, and it is predictable.
147
Gateways to Sensation
• The rods and cones are the eye’s photoreceptors in the retina.
• The rods specialize in peripheral vision, night vision, seeing
black and white, and detecting movement.
• The cones, found exclusively in the fovea and otherwise
toward the middle of the eye, specialize in color vision, acuity,
and daylight vision.
Our ability to see colors is explained by the trichromatic theory (in
the retina) and by the opponent-process theory (in the visual system
beyond the eyes).
• The rods and cones differ in color sensitivity. Yellowish green
is brightest for cones, blue-green for the rods (although they
will see it as colorless).
• Total color blindness is rare, but 8 percent of males and 1 percent of females are red-green color-weak. Color weakness is a
sex-linked trait carried on the X chromosome. The Ishihara
test is used to detect color blindness and color weakness.
Attention Voluntarily focusing on a specific sensory input.
Interpretation Where pain is concerned, the meaning given to a
stimulus.
Counterirritation Using mild pain to block more intense or longlasting pain.
148
CHAPTER 4
• Dark adaptation, an increase in sensitivity to light, is caused
mainly by increased concentration of visual pigments in both
the rods and the cones but mainly by rhodopsin recombining
in the rods. Vitamin A deficiencies may cause night blindness.
Sound waves are transduced by the eardrum, auditory ossicles, oval
window, cochlea, and ultimately, hair cells.
• Frequency theory explains how we hear tones up to 4,000
hertz; place theory explains tones above 4,000 hertz.
• Two basic types of hearing loss are conductive hearing loss and
sensorineural hearing loss.
• Noise-induced hearing loss is a common form of sensorineural
hearing loss caused by exposure to loud noise.
Olfaction (smell) and gustation (taste) are chemical senses responsive
to airborne or liquefied molecules.
• It is also suspected that humans are sensitive to pheromones,
although the evidence for this sense remains preliminary.
• The lock and key theory of olfaction partially explains smell.
In addition, the location of the olfactory receptors in the nose
helps identify various scents.
• Sweet and bitter tastes are based on a lock-and-key coding of
molecule shapes. Salty and sour tastes are triggered by a direct
flow of ions into taste receptors.
The somesthetic senses include the skin senses, kinesthesis, and the
vestibular senses.
• The skin senses are touch, pressure, pain, cold, and warmth.
Sensitivity to each is related to the number of receptors found
in an area of skin.
• Distinctions can be made among various types of pain, including visceral pain, somatic pain, referred pain, warning system
pain, and reminding system pain.
• Various forms of motion sickness are related to messages
received from the vestibular system, which detects gravity and
movement.
• According to sensory conflict theory, motion sickness is
caused by a mismatch of visual, kinesthetic, and vestibular sensations. Motion sickness can be avoided by minimizing sensory
conflict.
Incoming sensations are affected by sensory adaptation (a reduction
in the number of nerve impulses sent), by selective attention (selection
and diversion of messages in the brain), and by sensory gating (blocking or alteration of messages flowing toward the brain).
• Selective gating of pain messages apparently takes place in the
spinal cord. Gate control theory proposes an explanation for
many pain phenomena, except phantom limb pain.
Pain can be reduced or controlled by altering factors that affect pain
intensity.
• Pain is greatly affected by anxiety, control over the stimulus,
attention, and the interpretation placed on an experience
• Pain can be reduced by controlling these factors through distraction, reinterpretation, counterirritation.
Web Resources
For an up-to-date list of direct links to interesting sites, including
those listed here, visit the student companion site for this book at
www.cengage.com/psychology/coon
Psychophysics Explore absolute and discrimination thresholds as
well as other psychophysics phenomena.
The Joy of Visual Perception An online book about visual perception, including information on the eye.
Virtual Tour of the Ear This site provides educational information
about the ear and hearing and provides quick access to ear and hearing Web resources.
Taste and Smell Disorders Read about various disorders of taste and
smell and what can be done about them.
American Pain Foundation Find out more about pain and its treatment.
Interactive Learning
Introduction to Psychology: Gateways to Mind and Behavior Book
Companion Website
www.cengage.com/psychology/coon
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practice quizzes, web links, and more to help you study.
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CHAPTER
5
Perceiving the World
Gateway Theme
We actively construct our perceptions out of the information provided by our senses and our
past experience; the resulting perceptions are not always accurate representations of events.
© 2006 “Pintos” by Bev Doolittle®, courtesy of The Greenwich Workshop, Inc. www.greenwichworkshop.com
Gateway Questions
• In general, how do we construct our perceptions?
• Is perception altered by attention, motives, and emotions?
• What basic principles do we use to group sensations into
meaningful patterns?
•
What are perceptual constancies, and what is their role in
perception?
•
•
•
•
•
How is it possible to see depth and judge distance?
What effect does learning have on perception?
To what extent do we see what we expect to see?
Is extrasensory perception possible?
How can I learn to perceive events more accurately?
149
preview
Murder!
One of your authors was in a supermarket when an 8-year-old
girl suddenly came running around a corner. She looked back
and screamed, “Stop! Stop! You’re killing him! You’re killing my
father!” Here is your author’s account of what followed:
I retraced the girl’s path and saw two men on the floor, struggling violently. The guy on top had his victim by the throat.
There was blood everywhere. It was a murder in progress!
As a witness, I would have told a jury what I just told you,
were it not for an important fact: No murder ever took place
that day at the supermarket. When the police arrived, they
quickly discovered that the “guy on the bottom” had passed
out and hit his head. That caused the cut (actually quite
minor) that explained the “blood everywhere.” The “guy on
top” saw the first man fall and was trying to loosen his collar.
Perception: That Extra Step
“Marilyn Numerisée #420” © Yvaral 1990, Courtesy Circle Gallery
Gateway Question: In general, how do we construct our perceptions?
You wake up. Without a hint of effort, you see the rising sun.
I see the sunrise because my retinas send information to my brain,
right? It may seem as if incoming sensations automatically give rise
Visual perception involves finding meaningful patterns in complex stimuli. If
you look closely at this painting by the artist Yvaral, you will see that it is entirely
made up of small, featureless squares. A computer would have no clue what
these squares portray. Likewise, an infant or newly sighted person would see
only a jumble of meaningless colors. But because the squares form a familiar pattern, you should easily see Marilyn Monroe’s face. (Or is that Madonna?).
150
Obviously, the girl had misunderstood what was happening
to her father. As a psychologist, I still find it fascinating that
her words so dramatically influenced what I saw.
In the last chapter we discussed sensation, the process of
bringing information into the nervous system. This chapter is
about perception, or how we assemble sensations into meaningful patterns. As we perceive events, the brain actively selects,
organizes, and integrates sensory information to construct a
“picture” or model of the world. This process is so automatic
that it can take a drastic misperception like that of your author
to call attention to it.
Perception creates faces, melodies, works of art, illusions,
and on occasion, “murders” out of the raw material of sensation.
Let’s see how this takes place.
to your experiences. But they don’t. It takes the extra step known
as perception. Like most experiences, seeing a “sunrise” is a perceptual construction, or mental model of an event, that is actively
created by your brain.
To better understand perception, think again of the eye as
being like a digital camera. Both eye and camera focus light on
image-capturing surfaces. Both send information onward — your
eyes to the brain and the camera first to a memory chip, and from
there to your computer. But what happens when your computer
receives a digital image? Does the computer recognize that photo
of you and your best friend sitting on a beach last summer? Actually, not at all, because computers store photos as lists of numbers.
Each number tells the computer what color and brightness to turn
on a particular dot (pixel) on the screen. This allows your computer to display the photo, but the computer has no clue about
what that photo means.
In sharp contrast, when you look at a scene, you don’t just
mindlessly record the action potentials from your rods and cones.
Instead, you recognize and understand patterns in the messages.
This is what creates a perceptual experience, such as seeing a sunrise or a photograph.
It is easy to take perception for granted, but computer scientists
have had great difficulty creating even rudimentary artificial
vision. For instance, it is not yet possible for video surveillance
systems in stores to tell if a robbery is in progress and call the
police. And yet, you have had such a system since you were an
infant: Your senses send data to your brain, which creates meaningful perceptions of the world around you. If you were in line at
a grocery store, you would know in an instant if a robbery were
taking place. In other words, current computer systems are great at
capturing, storing, and displaying huge volumes of data, but they
Perceiving the World
are not yet very good at recognizing or understanding any of it. In
contrast, your brain is very good at it. In this chapter we will
explore perception, to learn how that extra step takes place.
Bottom-Up and Top-Down Processing
Moment by moment, our perceptions are typically constructed in
both bottom-up and top-down fashion. Think about the process of
building a house: Raw materials, such as lumber, doors, tiles, carpets, screws, and nails, must be painstakingly fit together. At the
same time, a building plan guides how the raw materials are
assembled.
Our brain builds perceptions in similar ways. In bottom-up
processing, we start constructing at the “bottom,” with raw materials. That is, we begin with small sensory units (features), and
build upward to a complete perception. The reverse also occurs. In
top-down processing, preexisting knowledge is used to rapidly
organize features into a meaningful whole (Goldstein, 2007). If
you put together a picture puzzle you’ve never seen before, you are
relying mainly on bottom-up processing: You must assemble small
pieces until a recognizable pattern begins to emerge. Top-down
processing is like putting together a puzzle you have solved many
times: After only a few pieces are in place, your past experience
gives you the plan to rapidly fill in the final picture.
Both types of processing are illustrated by Figure 5.1. Also,
look ahead to Figure 5.6. The first time you see the photo you
probably will process it bottom-up, by picking out features. The
next time, because of top-down processing, you’ll likely recognize
the photo instantly. Now that you have the general idea, let’s look
at perception in more detail.
•
•
151
Perception and Attention —
May I Have Your . . . Attention!
Gateway Question: Is perception altered by attention, motives, and
emotions?
You are surrounded by sights, sounds, odors, tastes, and touch
sensations. Which are you aware of ? The first stage of perception
is usually attention. As you may recall from Chapter 4, selective
attention refers to the fact that we give some messages priority
and put others on hold (Klein, 2004). (What if you can’t easily
focus your attention? See “Pay Attention!” to find out.) You might
find it helpful to think of selective attention as a bottleneck, or narrowing in the information channel linking the senses to perception. When one message enters the bottleneck, it seems to prevent
others from passing through ( Figure 5.2). Imagine, for instance,
that you are driving a car and approaching an intersection. You
need to be sure the traffic light is still green. Just as you are about
to check it, your passenger points to a friend at the side of the road.
If you then fail to notice the light just changed to red, an accident
may be just seconds away.
Have you ever felt overloaded when trying to do several things
at once? Divided attention arises when you must divide your
mental effort among tasks, each of which requires more or less
attention. Divided attention is related to our limited capacity for
storing and thinking about information. For example, when people first learn to drive, almost all their attention is needed to steer,
•
5.2 The attentional “spotlight”
•canFigure
be widened or narrowed. If you focus on
local details in this drawing you will see the
letter A repeated 13 times. If you broaden your
field of attention to encompass the overall
pattern, you will see the letter H. (After Lamb &
Art © Estate of Al Held/Licensed by VAGA, NY, NY
Yund, 1996.)
Figure 5.1 This painting by abstract artist Al Held is 9 feet by 9 feet. If you
•process
the painting “bottom-up,” all you will see is two small dark geometric
shapes. Would you like to try some top-down processing? Knowing the painting’s
title will allow you to apply your knowledge and see the painting in an entirely different way. The title? It’s The Big N. Can you see it now?
Perception The mental process of organizing sensations into
meaningful patterns.
Perceptual construction A meaningful mental model of external
events.
Bottom-up processing Organizing perceptions by beginning with
low-level features.
Top-down processing Applying higher-level knowledge to rapidly
organize sensory information into a meaningful perception.
Selective attention Giving priority to a particular incoming sensory
message.
Divided attention Allotting mental space or effort to various tasks or
parts of a task.
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CHAPTER 5
T HE C LIN ICA L FI LE
Pay Attention!
What if you can’t? What if your everyday experience is a giant kaleidoscope of rapidly shifting sensory impressions and thoughts? Easily
distracted, you may not even notice your
teacher exhorting you yet again to “Focus on
your work!” Couple that with an inability to
sit quietly at your desk and a tendency to say
or do the first thing that pops into your mind
and you will likely not be teacher’s pet or at
the top of your class.
People with attention deficit hyperactivity disorder (ADHD) have difficulty
controlling their attention and are prone to
display hyperactive and impulsive behavior
(DSM-IV-TR, 2000). According to the National
Institute of Mental Health, over two million
American children have ADHD and about
half will continue to show some symptoms as
adults (NIMH, 2008).
The diagnosis of ADHD is very controversial. On the one side are those who insist
that ADHD is a biological disorder that is best
treated with medications like Ritalin, a stimulant that exerts a curiously calming effect.
On the other side are those who insist that
ADHD is far too often overdiagnosed or misdiagnosed and that giving millions of young
children drugs is inappropriate and wrong
(Bratter, 2007). Complicating matters is the
fact that boys are over twice as likely to be
Charles Platiau/Reuters/Corbis
brake, shift, and so forth. However, as a skill becomes more automatic, it requires less attention. In driving, greater skill frees mental capacity for other things, such as tuning the car’s radio or carrying on a conversation. Yet even as some driving skills become
automated, divided attention can be hazardous (Wester et al.,
2008). Many automobile accidents occur when drivers are looking
at friends at the side of the road, using cell phones, tending to
children, reading maps, touching up their makeup, and the like.
Are some stimuli more attention getting than others? Yes. Very
intense stimuli usually command attention. Stimuli that are
brighter, louder, or larger tend to capture attention: A gunshot in
a library would be hard to ignore. If a brightly colored hot-air bal-
In many sports, experts are much better than beginners at paying attention to
key information. Compared with novices, experts scan actions and events more
quickly and focus on only the most meaningful information. This allows experts
to make decisions and react more quickly (Bard, Fleury, & Goulet, 1994).
diagnosed with ADHD than girls (Froehlich
et al., 2007), leading some critics to claim
that parents and teachers should give their
exuberant boys more time to actively play
outdoors rather than forcing them to sit still
indoors for hours at a time.
Is ADHD a real biological disorder or
an unfair label applied to active children?
Hopefully further research will answer this
important question. Until then, your authors
are content to note that this controversy
highlights a major theme of this chapter,
namely that perception is partly in the eye
of the beholder. (You were paying attention,
weren’t you?)
loon ever lands at your college campus, it will almost certainly
draw a crowd.
Repetitious stimuli, repetitious stimuli, repetitious stimuli, repetitious stimuli, repetitious stimuli, repetitious stimuli are also attention getting. A dripping faucet at night makes little noise by normal standards, but because of repetition, it may become as attention
getting as a single sound many times louder. This effect is used
repeatedly, so to speak, in television and radio commercials.
ATTENTION IS ALSO FREQUENTLY RELATED TO
contrast OR change IN STIMULATION. The contrasting type
styles in the preceding sentence draw attention because they are
unexpected. Geoffrey Loftus and Norman Mackworth (1978)
found that people who look at drawings like Figure 5.3 focus first
and longest on unexpected objects (the octopus, in this case).
•
Figure 5.3 One of the drawings used by Loftus and Mackworth (1978) to
•investigate
attention. Observers attend to unexpected objects longer than they do
to expected objects. In this drawing, observers looked longer at the octopus than
they did at a tractor placed in the same spot. What do you think would happen if a
tractor were shown upside down or on the roof of the barn?
Perceiving the World
Inattentional Blindness
As we take in information, attention is the key that unlocks the door
to perception. In fact, psychologists Arien Mack and Irvin Rock
believe that perception cannot occur without attention. Let’s say, for
example, that you are staring intently at a computer screen, waiting
to see if a black cross will appear. The cross flashes on the screen for
a split second and you say, “Yes I saw the cross.” At the same time, a
small blue square is flashed near the cross, also for a split second. Do
you see it, too? Amazingly, when people are tested in this way, many
never see the blue square. While their attention is intensely focused
on one object, they are blind to another—even though it is right in
front of their eyes. The image of the blue square falls on the retina,
but it might as well be invisible. Mack and Rock call this effect inattentional blindness (blindness caused by not attending to a stimulus) (Mack & Rock, 1998). Not seeing something that is plainly
before your eyes is most likely to occur when your attention is narrowly focused (Mack, 2002; Most et al., 2005).
Inattentional blindness is vividly illustrated by a study in which
participants were shown a film of two basketball teams, one wearing black shirts and the other wearing white. Observers were asked
to watch the film closely and count how many times a basketball
passed between members of one of the teams, while ignoring the
other team. As observers watched and counted, a person wearing a
gorilla suit walked into the middle of the basketball game, faced the
camera, thumped its chest, and walked out of view. Half the observers failed to notice this rather striking event (Simons & Chabris,
1999). This effect probably explains why fans of opposing sports
teams often act as if they had seen two completely different games.
In a similar way, using a cell phone while driving can cause inattentional blindness. Instead of ignoring a gorilla, you might miss seeing another car, a motorcyclist, or a pedestrian while your attention
is focused on the phone (Bressan & Pizzighello, 2008).
153
may play without your really attending to it. When a stimulus is
repeated without change, the OR habituates, or decreases. (Also,
see “The ‘Boiled Frog Syndrome.’”)
Interestingly, creative people habituate more slowly than average. We might expect that they would rapidly become bored with
a repeated stimulus. Instead, it seems that creative people actively
attend to stimuli, even those that are repeated (Colin, Moore, &
West, 1996).
Motives, Emotions, and Perception
Our motives and emotions also play a role in shaping our perceptions. For example, if you are hungry, food-related words are more
likely to gain your attention than nonfood words (Mogg et al.,
1998). Advertisers, of course, know that their pitch will be more
effective if it gets your attention. That’s why ads are loud, repetitious, and often intentionally irritating. They also take advantage
of two motives that are widespread in our society: anxiety and sex.
Everything from mouthwash to automobile tires is merchandised
by using sex to gain attention (LaTour & Henthorne, 2003). Other
ads combine sex with anxiety. Deodorant, soaps, toothpaste, and
countless other articles are pushed in ads that play on desires to be
attractive, to have “sex appeal,” or to avoid embarrassment.
Our emotions can also influence what we perceive. According
to psychologist Barbara Frederickson, negative emotions generally
narrow our perceptual focus or “spotlight.” This increases the likelihood of inattentional blindness. In contrast, positive emotions
can actually broaden the scope of attention (Fredrickson & Branigan, 2005). For example, we are much better at recognizing faces
of people from our own race than from others. (This other-race
effect is discussed in more detail later). But when people are in
positive moods, their ability to recognize people from other races
improves ( Johnson & Fredrickson, 2005).
Habituation
KNOWL E DG E B U I L DE R
Change, contrast, and incongruity are perhaps the most basic
sources of attention. We quickly habituate (respond less) to predictable and unchanging stimuli. Notice that repetition without
variation leads to habituation. Repetition is attention getting
when it is irritating or annoying. A dripping faucet varies in timing
just enough to gain attention. In contrast, we quickly habituate to
the steady tick of a clock.
How does habituation differ from sensory adaptation? As described
in Chapter 4, adaptation decreases the actual number of sensory messages sent to the brain. When messages do reach the brain, the body
has a sort of “What is it?” reaction, known as an orientation response.
An orientation response (OR) prepares us to receive information
from a stimulus: The pupils enlarge, brain-wave patterns shift, breathing stops briefly, blood flow to the head increases, and we turn
toward the stimulus. Have you ever seen someone stop to take a second look? If so, you have observed an orientation response.
Now, think about what happens when you download some new
music for your MP3 player. At first the music holds your attention
all the way through. But when the music becomes “old,” the song
Perception and Attention
RECITE
1. In top-down processing of information, individual features are analyzed and assembled into a meaningful whole. T or F?
2. Selective attention is promoted by all but one of the following.
Which does not fit?
a. habituation
b. contrast
c. change
d. intensity
Continued
Attention deficit hyperactivity disorder (ADHD) Disorder usually
arising in early childhood characterized by inattention, hyperactivity,
and impulsiveness.
Inattentional blindness Failure to perceive a stimulus that is in plain
view, but not the focus of attention.
Habituation A decrease in perceptual response to a repeated stimulus.
Orientation response Bodily changes that prepare an organism to
receive information from a particular stimulus.
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CHAPTER 5
C R IT ICAL T H I N KI N G
The “Boiled Frog Syndrome”
nuclear warheads, degradation of the environment, global deforestation, global warming, erosion of the ozone layer, and runaway
human population growth.
Robert Ornstein, a psychologist, and Paul
Ehrlich, a biologist, believe that many of the
large-scale threats we face are similar to the “boiled frog syndrome.”
Frogs placed in a pan of water that
is slowly heated cannot detect
the gradual rise in temperature.
They will sit still until they die.
Like the doomed frogs, many
people seem unable to detect
Randy Ury/Corbis
As we have noted, the perceptual system
is impressed most by dramatic changes.
Humans evolved to detect sharp changes
and distinctive events, such as the sudden
appearance of a lion, a potential mate, or
sources of food. We are far less able to detect
gradual changes.
Perceptual capacities that aided survival when humans were hunters
and gatherers may now be a
handicap. Many of the threats
facing civilization develop
v e r y s l o w l y. E x a m p l e s
include the stockpiling of
3. The occurrence of an orientation response shows that habituation is
complete. T or F?
4. Changes in brain waves and increased blood flow to the head are
part of an OR. T or F?
5. Research shows that positive emotions can broaden the “attentional
spotlight.” T or F?
REFLECT
Critical Thinking
6. Cigarette advertisements in the United States are required to carry a
warning label about the health risks of smoking. How have tobacco
companies made these labels less visible?
Relate
Have you ever tried to listen to two people who were talking to you at
the same time? What happens to your ability to process information
when there’s a conflict in selective attention?
You have almost certainly misperceived a situation at some time
because of the influence of motives or perceptions. How were your perceptions influenced?
gradual but deadly trends in modern civilization (Ornstein & Ehrlich, 1989).
To avoid disasters, it may take a conscious
effort by large numbers of people to see
the “big picture” and reverse lethal but easily overlooked patterns (O’Neill, 2005). The
relatively new field of community psychology
is dedicated to helping overcome our own
narrow perspectives to perceive important
larger patterns (Nelson & Prilleltensky, 2005).
Understanding how perception shapes “reality” may ultimately prove to be a matter of life
or death. Are you paying attention?
richness of your newfound visual experience but, like a computer,
be unable to recognize any of it.
You’re kidding, right? Nope. Newly sighted persons must learn to
recognize objects, to read clocks, numbers, and letters, and to judge
sizes and distances (Gregory, 2003). For instance, a cataract patient
named Mr. S. B. had been blind since birth. After an operation
restored his sight at age 52, Mr. S. B. struggled to use his vision.
Mr. S. B. soon learned to tell time from a large clock and to read
block letters he had known only from touch. At a zoo, he recognized an elephant from descriptions he had heard. However, handwriting meant nothing to him for more than a year after he
regained sight, and many objects were meaningless until he
touched them. Thus, Mr. S. B. slowly learned to organize his sensations into meaningful perceptions.
Gestalt Principles
How are sensations organized into perceptions? The Gestalt psychologists proposed that the simplest organization is constructed
by grouping some sensations into an object, or figure, that stands
out on a plainer background (Goldstein, 2007). Figure-ground
organization is probably inborn, because it is the first perceptual
ability to appear after cataract patients regain sight. In normal
figure-ground perception, only one figure is seen. In reversible figures, however, figure and ground can be switched. In Figure 5.4
it is equally possible to see either a wineglass figure on a dark background or two face profiles on a light background. As you shift
from one pattern to the other, you should get a clear sense of what
figure-ground organization means.
Answers: 1. F 2. a 3. F 4. T 5. T 6. Advertisers place health warnings in the
corners of ads, where they attract the least possible attention. Also, the
labels are often placed on “busy” backgrounds so that they are partially
camouflaged. Finally, the main images in ads are designed to strongly
attract attention. This further distracts readers from seeing the warnings.
•
Perceptual Organization —
Getting It All Together
Gateway Question: What basic principles do we use to group
sensations into meaningful patterns?
What would it be like to have your vision restored after a lifetime
of blindness? Actually, a first look at the world can be disappointing because your newfound ability to sense the world does not
guarantee that you can perceive it. You may be thrilled by the sheer
bridges
See Chapter 1, page 24, for a brief history of Gestalt
psychology.
Perceiving the World
155
• Figure 5.4 A reversible figure-ground design. Do you see two faces in profile or a wineglass?
Are there other Gestalt organizing principles? The Gestalt psychologists identified several other principles that bring some order
to your perceptions ( Figure 5.5).
•
1. Nearness. All other things being equal, stimuli that are near
each other tend to be constructed, or grouped, together
(Quinn, Bhatt, & Hayden, 2008). Thus, if three people stand
near each other and a fourth person stands 10 feet away, the
adjacent three will be seen as a group and the distant person
as an outsider (see Figure 5.5a).
2. Similarity. “Birds of a feather flock together,” and stimuli
that are similar in size, shape, color, or form tend to be
grouped together (see Figure 5.5b). Picture two bands
marching side by side. If their uniforms are the same colors, the bands will be seen as one large group, not as two
separate groups.
3. Continuation, or continuity.
Perceptions tend toward simplicity
and continuity. In Figure 5.5c it
is easier to visualize a wavy line on a
squared-off line than it is to see a complex row of shapes.
4. Closure. Closure refers to the tendency to complete a figure so that it
has a consistent overall form. Each
of the drawings in Figure 5.5d has
one or more gaps, yet each is perceived as a recognizable figure. The
“shapes” that appear in the two right
drawings in Figure 5.5d are illusory
figures (implied shapes that are not
actually bounded by an edge or an
outline). Even young children see
these shapes, despite knowing that
they are “not really there.” Illusory figures reveal that our tendency to form
shapes — even with minimal cues — is
powerful.
•
•
(a) Principle of nearness
Notice how differently a group of six
objects can be perceptually organized,
depending on their spacing.
•
(b) Principle of similarity
In these examples, organization
depends on similarity of color.
•
Similarity and nearness can
be combined to produce a new
organization.
(c) Principle of continuity
•
This?
plus
or
This?
(d) Principle of closure
(e) Principle of common region
• Figure 5.5 How we organize perceptions.
Figure-ground organization Part of
a stimulus appears to stand out as an
object (figure) against a less prominent
background (ground).
156
CHAPTER 5
•
interpretation). If you look at a cloud, you may discover dozens of
ways to organize its contours into fanciful shapes and scenes. Even
clearly defined stimuli may permit more than one interpretation.
Look at Necker’s cube in Figure 5.7 if you doubt that perception
is an active process. Visualize the top cube as a wire box. If you
stare at the cube, its organization will change. Sometimes it will
seem to project upward, like the lower left cube; other times it will
project downward. The difference lies in how your brain interprets the same information. In short, we actively construct meaningful perceptions; we do not passively record the events and
stimuli around us (Coren, Ward, & Enns, 2004).
In some instances, a stimulus may offer such conflicting information that perceptual organization becomes impossible. For example,
the tendency to make a three-dimensional object out of a drawing is
frustrated by the “three-pronged widget” ( Figure 5.8), an impossible figure. Such patterns cannot be organized into stable, consistent, or meaningful perceptions. If you cover either end of the drawing in Figure 5.8, it makes sense perceptually. However, a problem
arises when you try to organize the entire drawing. Then, conflicting
information prevents you from forming a stable perception.
Learning to organize his visual
sensations was only one of the
hurdles Mr. S. B. faced in learning
to see. In the next section, we will
consider some others.
5. Contiguity. A principle that can’t be shown in Figure 5.5
is contiguity, or nearness in time and space. Contiguity is
often responsible for the perception that one thing has caused
another (Buehner & May, 2003). A psychologist friend of
ours demonstrates this principle in class by knocking on his
head with one hand while knocking on a wooden table (out
of sight) with the other. The knocking sound is perfectly
timed with the movements of his visible hand. This leads to
the irresistible perception that his head is made of wood.
6. Common region. As you can see in Figure 5.5e, stimuli
that are found within a common area tend to be seen as a
group (Palmer, & Beck, 2007). On the basis of similarity
and nearness, the stars in Figure 5.5e should be one group
and the dots another. However, the colored backgrounds
define regions that create three groups of objects (four stars,
two stars plus two dots, and four dots). Perhaps the principle
of common region explains why we tend to mentally group
together people from a particular country, state, province, or
geographic region.
•
•
•
•
•
Clearly, the Gestalt principles offer us some basic “plans” for organizing parts of our day-to-day perceptions in top-down fashion. So
too does learning and past experience. Take a moment and look for
the camouflaged animal pictured in Figure 5.6. (Camouflage patterns break up figure-ground organization). If you had never seen
similar animals before, could you have located this one? Mr. S. B.
would have been at a total loss to find meaning in such a picture.
In a way, we are all detectives, seeking patterns in what we see.
In this sense, a meaningful pattern represents a perceptual hypothesis, or initial plan or guess about how to organize sensations.
Have you ever seen a “friend” in the distance, only to have the
person turn into a stranger as you drew closer? Preexisting ideas
and expectations actively guide our interpretation of sensations
(Most et al., 2005).
The active, constructive nature of perception is perhaps most
apparent for ambiguous stimuli (patterns allowing more than one
•
E.R. Degginger/Animals Animals
•cube.Figure 5.7 Necker’s
Figure 5.8 (Above) An impossible
•figure
— the “three-pronged widget.”
Figure 5.6 A challenging example of perceptual organization. Once the cam•ouflaged
insect (known as a giant walking stick) becomes visible, it is almost impos-
(Below) It might seem that including more
information in a drawing would make
perceptual conflicts impossible. However,
Japanese artist Shigeo Fukuda has shown
otherwise. (“Disappearing Column” © Shigeo
sible to view the picture again without seeing the insect.
Fukuda, 1985.)
Perceiving the World
157
Perceptual Constancies —
Taming an Unruly World
Gateway Question: What are perceptual
constancies, and what is their role in perception?
When Mr. S. B. first regained his vision, he
could only judge distance in familiar situations
(Gregory, 1990). One day he was found crawling out of a hospital window to get a closer look
at traffic on the street. It’s easy to understand
his curiosity, but he had to be restrained. His
room was on the fourth floor!
Why would Mr. S. B. try to crawl out of a
fourth-story window? Couldn’t he at least tell
distance from the size of the cars? No, you must
be visually familiar with objects to use their size
to judge distance. Try holding your left hand a
(a)
(b)
few inches in front of your nose and your right
Figure
5.9
Shape constancy. (a) When a door is open, its image actually forms a trapezoid. Shape conhand at arm’s length. Your right hand should
stancy is indicated by the fact that it is still perceived as a rectangle. (b) With great effort you may be able to
appear to be about half the size of your left see this design as a collection of flat shapes. However, if you maintain shape constancy, the distorted squares
hand. Still, you know your right hand did not strongly suggest the surface of a sphere. (From Spherescapes-1 by Scott Walter and Kevin McMahon, 1983.)
suddenly shrink, because you have seen it many
times at various distances. We call this size constancy: The per(inborn). An example is the ability to see a line on a piece of paper.
ceived size of an object remains the same, even though the size of
Likewise, even newborn babies show some evidence of size conits image on the retina changes.
stancy (Granrud, 2006; Slater, Mattock, & Brown, 1990). HowTo perceive your hand accurately, you had to draw on past expeever, many of our perceptions are empirical, or based on prior
rience to provide a top-down plan for constructing your percepexperience. For instance, cars, houses, and people look like toys
tion. Some of these plans are so basic they seem to be native
when seen from a great distance or from an unfamiliar perspective,
such as from the top of a skyscraper. This suggests that although
some size constancy is innate, it is also affected by learning (Granrud, 2004).
In shape constancy the shape of an object remains stable, even
though the shape of its retinal image changes. You can demonstrate shape constancy by looking at this page from directly overhead and then from an angle. Obviously, the page is rectangular,
but most of the images that reach your eyes are distorted. Yet,
though the book’s image changes, your perception of its shape
remains constant. (For additional examples, see Figure 5.9.) On
the highway, alcohol intoxication impairs size and shape constancy, adding to the accident rate among drunk drivers (Farrimond, 1990).
Let’s say that you are outside in bright sunlight. Beside you, a
friend is wearing a gray skirt and a white blouse. Suddenly a cloud
shades the sun. It might seem that the blouse would grow dimmer,
but it still appears to be bright white. This happens because the
blouse continues to reflect a larger proportion of light than nearby
•
Mark Richards/PhotoEdit
•
Almost everyone’s family album has at least one photo like this. Extreme viewing
angles can make maintaining size constancy difficult, even for familiar objects.
Perceptual hypothesis An initial guess regarding how to organize
(perceive) a stimulus pattern.
Size constancy The perceived size of an object remains constant,
despite changes in its retinal image.
Shape constancy The perceived shape of an object is unaffected by
changes in its retinal image.
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CHAPTER 5
C R IT ICAL T H I N KI N G
A Bird’s-Eye View
Although it is tempting to assume that other
animals perceive depth much as we do, this
is not the case. Different species actually see
the world in rather different ways. Most variations in vision have a purpose. Evolutionary
psychologists theorize that human depth perception is an evolutionary holdover — from
life in the treetops. The superb depth perception that helped our distant ancestors swing
from branch to branch now helps us swing at
a softball or avoid erratic drivers in traffic.
It might seem that birds would have acute
stereoscopic vision, and some do. But most
•
birds are prey for other animals. When you
spend life as a potential meal, it’s important
to detect approaching predators (Waldvogel,
1990). That’s why many birds have an unusually wide field of view ( Figure 5.10a and b).
An extreme case is the American woodcock, a
bird that can survey a 360-degree panorama
without moving its eyes or head. The tradeoff for this wide-angle view is a very limited
area of binocular vision, where depth perception is strongest ( Figure 5.10c). But to the
woodcock, an ability to spot hungry preda-
•
•
tors is probably more valuable than depth
perception.
What does the world look like to a woodcock? Computer scientist Ping-Kang Hsiung
(1990) used optical ray-tracing to simulate
the woodcock’s view ( Figure 5.10e and f ).
As you can see in Figure 5.10, even a pretty
foxy predator would have trouble sneaking
up on a woodcock. When it comes to human
vision, perhaps it’s too bad that a little of
the woodcock’s wide-angle vision didn’t get
thrown in as well.
•
(a)
(b)
(c)
(d)
(e)
(f)
•
Figure 5.10 (a) When viewed from above the head, a human’s field of view for the right and left eyes contains a large area of overlapping, stereoscopic vision
(darker shading). (b) The barn swallow’s vision, like that of many birds, covers a much wider field of view than ours. Although the swallow’s area of binocular vision is
smaller than a human’s, the swallow has sharper peripheral vision. (c) A bird called the American woodcock can see all the way around its head. Binocular vision is limited to a narrow band, but an extremely wide field of view helps the woodcock detect predators. (Adapted from Waldvogel, 1990.) (d) This image, created by Ping-Kang
Hsiung (1990), shows how an imaginary scene would look to a person standing across the road from a rather strange hitchhiker. (e, f) This is what a woodcock’s left
and right eyes would see if the bird were at the same point as the human in view d. (Computer graphics courtesy of Dr. Hsiung.)
Perceiving the World
objects. Brightness constancy refers to the fact that the brightness
of objects appears to stay the same as lighting conditions change.
However, this holds true only if the blouse and other objects are all
illuminated by the same amount of light. You could make an area
on your friend’s gray skirt look whiter than the shaded blouse by
shining a bright spotlight on the skirt.
To summarize, the energy patterns reaching our senses are constantly changing, even when they come from the same object. Size,
shape, and brightness constancy rescue us from a confusing world
in which objects would seem to shrink and grow, change shape as
if made of rubber, and light up or fade like neon lamps.
One of the most amazing perceptual feats is our capacity to
construct the experience of three-dimensional space from flat retinal images. We’ll explore that topic in a moment, but first here’s a
chance to rehearse what you’ve learned.
K N O WL E D GE B U I L D E R
Gestalt Principles and Perceptual
Constancies
RECITE
1. The first and most basic perceptual organization to emerge when
sight is restored to a blind person is:
a. continuity
b. nearness constancy
c. recognition of numbers and letters
d. figure-ground
2. Gestalt principles offer us some basic “plans” for organizing parts of
our day-to-day perceptions in top-down fashion. T or F?
3. At times, meaningful perceptual organization represents a
__________________________ , or “guess,” held until the evidence
contradicts it.
4. The design known as Necker’s cube is a good example of an impossible figure. T or F?
5. Which among the following are subject to basic perceptual constancy?
a. figure-ground organization
b. size
c. ambiguity
d. brightness
e. continuity
f. closure
g. shape
h. nearness
REFLECT
Critical Thinking
6. People who have taken psychedelic drugs, such as LSD or mescaline, often report that the objects and people they see appear to
be changing in size, shape, and brightness. This suggests that such
drugs disrupt what perceptual process?
Relate
As you look around the area in which you are now, how are the Gestalt
principles helping to organize your perceptions? Try to find a specific
example for each principle.
If you needed to explain the perceptual constancies to a friend, what
would you say? Why are the constancies important for maintaining a
stable perceptual world?
159
Depth Perception — What if
the World Were Flat?
Gateway Question: How is it possible to see depth and judge distance?
Close one of your eyes, hold your head very still, and stare at a
single point across the room. If you don’t move your head or eyes,
your surroundings will appear to be almost flat, like a painting or
photograph. But even under these conditions you will still have
some sense of depth. Now, open both eyes and move your head
and eyes as usual. Suddenly, the “3-D” perceptual world returns.
How are we able to perceive depth and space?
Depth perception is the ability to see three-dimensional space and
to accurately judge distances. Without depth perception, another
form of top-down processing, you would be unable to drive a car or
ride a bicycle, play catch, shoot baskets, thread a needle, or simply
navigate around a room (Howard & Rogers, 2001,a). The world
would look like a flat surface. (See “A Bird’s-Eye View” on page 158.)
Mr. S. B. had trouble with depth perception after his sight was
restored. Is depth perception learned? Some psychologists (nativists)
hold that depth perception is inborn. Others (the empiricists)
view it as learned. Most likely, depth perception is partly learned
and partly innate (Witherington et al., 2005). Some evidence on
the issue comes from work with the visual cliff. Basically, a visual
cliff is a glass-topped table ( Figure 5.11). On one side a checkered surface lies directly beneath the glass. On the other side, the
checkered surface is 4 feet below. This makes the glass look like a
tabletop on one side and a cliff, or drop-off, on the other.
To test for depth perception, 6- to 14-month-old infants were
placed in the middle of the visual cliff. This gave them a choice of
crawling to the shallow side or the deep side. (The glass prevented
them from doing any “skydiving” if they chose the deep side.)
Most infants chose the shallow side. In fact, most refused the deep
side even when their mothers tried to call them toward it (Gibson
& Walk, 1960).
If the infants were at least 6 months old when they were tested,
isn’t it possible that they learned to perceive depth? Yes. More recent
research has shown that depth perception begins to develop as
early as 2 weeks of age (Yonas, Elieff, & Arterberry, 2002). It is
very likely that at least a basic level of depth perception is innate.
Yet, the development of depth perception is not complete until
about 6 months, suggesting that it depends on both brain maturation and individual experience.
Then why do some older babies crawl off tables or beds? As soon
as infants become active crawlers, they refuse to cross the deep side
of the visual cliff. However, older infants who have just learned to
walk must again learn to avoid the “deep” side of the visual cliff
•
Brightness constancy The apparent (or relative) brightness of objects
remains the same as long as they are illuminated by the same amount
of light.
Depth perception The ability to see three-dimensional space and to
accurately judge distances.
Answers: 1. d 2. T 3. hypothesis 4. F 5. b, d, g 6. Perceptual constancies
(size, shape, and brightness).
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CHAPTER 5
•
Figure 5.11 Human
infants and newborn animals refuse to go over the
edge of the visual cliff.
Glass over
patterned surface
Glass only
Shallow side
Mark Richards/PhotoEdit
Deep side
(Witherington et al., 2005). Besides, even babies who perceive
depth may not be able to catch themselves if they slip. A lack of
coordination — not an inability to see depth — probably explains
most “crash landings” after about 4 months of age.
We learn to construct our perception of three-dimensional
space by using a variety of depth cues. Depth cues are features of
the environment and messages from the body that supply information about distance and space. Some cues require two eyes (bin-
Stereoscopic: optic nerve
transmissions from each eye are
relayed to both sides of brain
Floor pattern
seen through
glass
ocular depth cues), whereas others will work with just one eye
(monocular depth cues).
Binocular Depth Cues
The most basic source of depth perception is retinal disparity (a
discrepancy in the images that reach the right and left eyes). Retinal disparity, which is a binocular cue, is based on the fact that the
eyes are about 2.5 inches apart. Because of this, each eye receives a
Binocular: both eyes
have overlapping
fields of vision
Allows depth perception
with accurate distance
estimation
Bob Western
(a)
•
(b)
Figure 5.12
(c)
(a) Stereoscopic vision. (b) The photographs show what the right and left eyes would see when viewing a plant. Hold the page about 6 to
8 inches from your eyes. Allow your eyes to cross and focus on the overlapping image between the two photos. Then try to fuse the leaves into one image. If you
are successful, the third dimension will appear like magic. (c) Now do the same with the random dot stereogram, but with your eyes 10 inches from the page. With
luck, you will see a diamond shape hovering over the background. (See text for explanation.) (Julesz, 1971)
161
© 2009 Magic Eye Inc. www.magiceye.com
Perceiving the World
•
Figure 5.13 This popular style of computer-generated art creates a 3-D illusion by superimposing two patterns. There are mismatches between some
areas of the two patterns. This simulates retinal disparity and creates a sensation of depth. To get the 3-D effect, hold the stereogram about 8 inches from the
end of your nose. Relax your eyes and look through the art, as if you were focusing on something in the distance. If you’re patient, you may see a 3-D globe.
slightly different view of the world. Try this: Put a finger in front
of your eyes and as close to your nose as you can. First close one eye
and then the other, over and over again. You should notice that
your finger seems to jump back and forth as you view the different
images reaching each eye. However, when the two different images
are fused into one overall image, stereoscopic vision (threedimensional sight) occurs (Howard & Rogers, 2001b). The result
is a powerful sensation of depth ( Figure 5.12).
Retinal disparity can be used to produce 3-D movies by filming
with two cameras separated by several inches. Later, both images
are simultaneously projected on a screen. Audience members wear
glasses that filter out one of the images to each eye. Because each
eye gets a separate image, normal stereoscopic vision is duplicated.
Try the following demonstration of retinal disparity and fusion.
•
Totally Tubular
Roll a piece of paper into a tube. Close your left eye. Hold the tube to your
right eye like a telescope. Look through the tube at some object in the distance. Place your left hand against the tube halfway down its length and in
front of your left eye. Now open your left eye. You should see a “hole” in your
hand. You couldn’t expect a professional photographer to do a better job of
blending the two images than your visual system does automatically.
How does retinal disparity produce depth? Perceiving depth is
more than a simple blending of two “pictures” of the world. In
Figure 5.12c you will find two random dot stereograms (patterns
of dots that produce an illusion of depth). Notice that they contain no objects, lines, or edges. Just the same, when the stereograms are properly viewed (one to each eye), a center area seems to
float above the background. Such designs show that the brain is
very sensitive to any mismatch of information from the eyes. In
Figure 5.12c, depth comes from shifting dots in the center of one
square so that they do not match dots in the other square (Howard
& Rogers, 2001a, 2000b; Julesz, 1971). (Also see Figure 5.13.)
To a large extent our experience of three-dimensional space is
constructed from countless tiny differences between what the
right and left eyes see. Direct studies of the brain have shown that
visual areas do, in fact, contain cells that detect disparities (Cumming & DeAngelis, 2001).
Convergence is a second binocular depth cue. When you look at
a distant object, the lines of vision from your eyes are parallel. You
are normally not aware of it, but whenever you estimate a distance
under 50 feet (as when you play catch or shoot trash can hoops
with the first draft of your essay), you are using convergence.
How? Muscles attached to the eyeball feed information on eye
position to the brain to help it judge distance ( Figure 5.14).
•
5.14
•TheFigure
eyes must converge, or turn in toward the nose, to focus close objects.
The eyes shown are viewed from above the head.
•
•
•
Depth cues Perceptual features that impart information about distance
and three-dimensional space.
Binocular depth cues Perceptual features that impart information
about distance and three-dimensional space that require two eyes.
Monocular depth cues Perceptual features that impart information
about distance and three-dimensional space that require just one eye.
Stereoscopic vision Perception of space and depth caused chiefly by
the fact that the eyes receive different images.
162
CHAPTER 5
(a)
(b)
(c)
(d)
(e)
Figure 5.15 (a) Linear perspective. (b) Relative size. (c) Light and shadow. (d) Overlap. (e) Texture gradients. Drawings in the top row show fairly “pure”
•examples
of each of the pictorial depth cues. In the bottom row, the pictorial depth cues are used to assemble a more realistic scene.
You can feel convergence by exaggerating it: Focus on your
fingertip and bring it toward your eyes until they almost cross. You
can actually feel the muscles that control eye movement working
harder and harder as your fingertip gets closer. If you repeat this
little exercise with one eye shut, you will feel no increase in muscle
tension as your finger gets closer. It takes both eyes to converge.
This is why we say convergence is also a binocular depth cue.
If disparity and convergence are so important, can a person with
one eye perceive depth? Yes, but not as well as a person with two
eyes. Overall, stereoscopic vision is 10 times better for judging
depth than perception based on just one eye (Rosenberg, 1994).
Try driving a car or riding a bicycle with one eye closed. You will
find yourself braking too soon or too late, and you will have difficulty estimating your speed. (“But officer, my psychology text said
to . . .”) Despite this, you will be able to drive, although it will be
more difficult than usual. This is possible because your single eye
is making use of monocular depth cues.
Monocular Depth Cues
As their name implies, monocular depth cues can be used to construct a three-dimensional perception with information received
from just one eye (Sekuler & Blake, 2006). One such cue is accommodation, the bending of the lens to focus on nearby objects.
Sensations from muscles attached to each lens flow back to the
brain. Changes in these sensations help us judge distances within
about 4 feet of the eyes. This information is available even if you
are just using one eye, so accommodation is a monocular cue.
Beyond 4 feet though, accommodation has limited value. Obviously, it is more important to a watchmaker or a person trying to
thread a needle than it is to a basketball player or someone driving
an automobile.
Other monocular depth cues are also referred to as pictorial
depth cues, because a good movie, painting, or photograph can
create a convincing sense of depth where none exists.
How is the illusion of depth created on a two-dimensional surface?
Pictorial depth cues are monocular cues found in paintings,
drawings, and photographs that impart information about space,
depth, and distance. To understand how these cues work, imagine
that you are looking outdoors through a window. If you trace
everything you see onto the glass, you will have an excellent drawing, with convincing depth. If you then analyze what is on the glass
you will find the following features ( Figure 5.15):
•
1. Linear perspective. This cue is based on the apparent convergence of parallel lines in the environment. If you stand
between two railroad tracks, they appear to meet near the
horizon, even though they actually remain parallel. Because
you know they are parallel, their convergence implies great
distance ( Figure 5.15a).
2. Relative size. If an artist wishes to depict two objects of the
same size at different distances, the artist makes the more distant object smaller ( Figure 5.15b). Special effects in films
create sensational illusions of depth by rapidly changing the
image size of planets, airplanes, monsters, or what have you.
(Also see Figure 5.16.)
•
•
•
Linear perspective is a very powerful
cue for depth. Because of the depth
cues implied in this drawing, the upper
cross on the vertical line appears to be
diagonal. It is actually a right angle. The
lower cross, which appears to be a right
angle, is actually diagonal to the vertical
line. (After Enns & Coren, 1995.)
Dennis Coon
Figure 5.16 On a dry lake bed, relative size is just about the only depth cue
•available
for judging the camera’s distance from this vintage aircraft. What do you
estimate the distance to be? For the answer, look ahead to • Figure 5.21.
3. Height in the picture plane. Objects that are placed higher
(closer to the horizon line) in a drawing tend to be perceived
as more distant. In the upper frame of Figure 5.15b the
black columns look like they are receding into the distance
partly because they become smaller but also because they
move higher in the drawing.
4. Light and shadow. Most objects are lighted in ways that
create clear patterns of light and shadow. Copying such patterns of light and shadow can give a two-dimensional design
a three-dimensional appearance ( Figure 5.15c). (Also, look
ahead to Figure 5.17 for more information on light and
shadow.)
5. Overlap. Overlap (or interposition) occurs when one object
partially blocks another object. Hold your hands up and ask
a friend across the room which is nearer. Relative size will
give the answer if one hand is much nearer to your friend
than the other. But if one hand is only slightly closer than
the other, your friend may not be able to tell — until you slide
one hand in front of the other. Overlap then removes any
doubt ( Figure 5.15d ).
6. Texture gradients. Changes in texture also contribute to
depth perception. If you stand in the middle of a cobblestone
street, the street will look coarse near your feet. However, its
texture will get smaller and finer if you look into the distance
( Figure 5.15e).
7. Aerial perspective. Smog, fog, dust, and haze add to the
apparent distance of an object. Because of aerial perspective,
distant objects tend to be hazy, washed out in color, and
lacking in detail. Aerial haze is often most noticeable when
it is missing. If you have ever seen a distant mountain range
on a crystal-clear day, it might have looked like it was only a
few miles away. In reality, you could have been viewing them
through 50 miles of crystal-clear air.
8. Relative motion. Relative motion, also known as motion
parallax (PAIR-ah-lax), can be seen by looking out a window and moving your head from side to side. Notice that
nearby objects appear to move a sizable distance as your head
moves. Trees, houses, and telephone poles that are farther
•
•
•
•
163
M.C. Escher’s “Convex and Concave” © 2009 The M.C. Escher Company-Holland. All rights reserved. www.mcescher.com
Perceiving the World
•
Figure 5.17 (Above) When judging depth we usually assume that light
•comes
mainly from one direction, usually from above. Squint a little to blur the
image you see here. You should perceive a collection of globes projecting
outward. If you turn this page upside down, the globes should become cavities.
(After Ramachandran, 1995.) (Below) The famed Dutch artist M. C. Escher violated our
assumptions about light to create the dramatic illusions of depth found in his 1955
lithograph Convex and Concave. In this print, light appears to come from all sides
of the scene. (Courtesy of the Collection Haags Gemeente Museum, The Hague. © 1994
M. C. Escher/Cordon Art, Baarn, The Netherlands. All rights reserved.)
away appear to move slightly in relation to the background.
Distant objects like hills, mountains, or clouds don’t seem to
move at all.
When combined, pictorial cues can create a powerful illusion
of depth. (See Table 5.1 for a summary of all the depth cues we
have discussed.)
Is motion parallax really a pictorial cue? Strictly speaking it is
not, except in the two-dimensional world of movies, television,
or animated cartoons. However, when parallax is present, we
almost always perceive depth. Much of the apparent depth of a
good movie comes from relative motion captured by the camera.
•
Pictorial depth cues Features found in paintings, drawings, and
photographs that impart information about space, depth, and distance.
164
CHAPTER 5
Table 5.1
• Summary of Visual Depth Cues
Binocular Cues
• Retinal disparity
• Convergence
Monocular Cues
• Accommodation
• Pictorial depth cues (listed below)
Linear perspective
Relative size
Height in the picture plane
Light and shadow
Overlap
Texture gradients
Aerial perspective
Relative motion (motion parallax)
•
Figure 5.18 illustrates the defining feature of motion parallax.
Imagine that you are in a bus and watching the passing scenery
(with your gaze at a right angle to the road). Under these conditions, nearby objects will appear to rush backward. Those farther
away, such as distant mountains, will seem to move very little or
not at all. Objects that are more remote, such as the sun or
moon, will appear to move in the same direction you are traveling. (That’s why the moon appears to “follow” you when you
take a stroll at night.)
Are pictorial depth cues universal? Not entirely. Some cultures
use only selected pictorial cues to represent depth. People in these
cultures may not easily recognize other cues (Deregowski, 1972).
For example, researcher William Hudson tested members of
remote tribes who do not use relative size to show depth in drawings. These people perceive simplified drawings as flat designs. As
you can see in Figure 5.19, they do not assume, as we do, that a
larger image means that an object is closer. Of course, members of
•
5.19 A Hudson test picture. Two-dimensional perceivers assume
•theFigure
hunter is trying to spear the distant elephant rather than the nearby antelope.
Some acquaintance with conventions for representing depth in pictures and photographs seems necessary. (From “Pictorial Perception and Culture” by J. B. Deregowski.
© 1972 Scientific American, Inc. All rights reserved.)
non-Western cultures can learn to interpret drawings of depth if
they are given a chance to practice (Mshelia & Lapidus, 1990).
The Moon Illusion
How do the depth perception cues relate to daily experience? We
constantly use both pictorial cues and bodily cues to sense depth
and judge distances. Consider an intriguing effect called the
moon illusion (perceiving the moon as larger when it is low in
the sky). When the moon is on the horizon, it tends to look like
a silver dollar. When it is directly overhead, it looks more like a
dime. Contrary to what some people believe, the moon is not
magnified by the atmosphere. But the moon looks nearly twice as
large when it’s low in the sky (Ross & Plug, 2002). This occurs,
in part, because the moon’s apparent distance is greater when it is
near the horizon than when it is overhead (Kaufman & Kaufman,
2000).
But if it seems farther away, shouldn’t it look smaller? No.
When the moon is overhead, few depth cues surround it. In
contrast, when you see the moon on the horizon, it is behind
houses, trees, telephone poles, and mountains. These objects
add numerous depth cues, which cause the horizon to seem
more distant than the sky overhead. Picture two balloons, one
10 feet away and the second 20 feet away. Suppose the more
distant balloon is inflated until its image matches the image of
the nearer balloon. How do we know the more distant balloon
is larger? Because its image is the same size as a balloon that is
closer. Similarly, the moon makes the same-size image on the
horizon as it does overhead. However, the horizon seems more
distant because more depth cues are present. As a result, the
horizon moon must be perceived as larger (Kaufman & Kaufman,
2000) ( Figure 5.20).
This explanation is known as the apparent-distance hypothesis (the horizon seems more distant than the night sky). You can
test it by removing depth cues while looking at a horizon moon.
Try looking at the moon through a rolled-up paper tube or make
your hands into a “telescope” and look at the next large moon you
see. It will immediately appear to shrink when viewed without
depth cues (Ross & Plug, 2002).
•
•
Direction of travel
Figure 5.18
The apparent motion of objects viewed during travel depends
on their distance from the observer. Apparent motion can also be influenced by
an observer’s point of fixation. At middle distances, objects closer than the point
of fixation appear to move backward; those beyond the point of fixation appear to
move forward. Objects at great distances, such as the sun or moon, always appear
to move forward.
Perceiving the World
165
KNOWL E DG E B U I L DE R
Depth Perception
RECITE
1. The visual cliff is used to test for infant sensitivity to linear perspective. T or F?
2. Write an M or a B after each of the following to indicate if it is a monocular or binocular depth cue.
accommodation _____ convergence _____ retinal disparity _____
linear perspective _____ motion parallax _____ overlap _____
relative size _____
3. Which of the depth cues listed in question 2 are based on muscular
feedback? ________________________________________.
4. Interpretation of pictorial depth cues requires no prior experience.
T or F?
5. The apparent distance hypothesis provides a good explanation of
the
a. moon illusion
b. horizontal-vertical illusion
c. Zulu illusion
d. effects of inattentional blindness
REFLECT
5.20 The Ponzo illusion may help you understand the moon illu•sion.Figure
Picture the two white bars as resting on the railroad tracks. In the drawing,
the upper bar is the same length as the lower bar. However, because the upper bar
appears to be farther away than the lower bar, we perceive it as longer. The same
logic applies to the moon illusion.
Critical Thinking
6. Scientists believe that the famous Dutch artist Rembrandt had a
visual defect that prevented him from perceiving depth. (He had a
wandering eye.) How might this have aided him as an artist?
Relate
Part of the rush of excitement produced by action movies and video
games is based on the sense of depth they create. Return to the list of
pictorial depth cues. What cues have you seen used to portray depth? Try
to think of specific examples in a movie or game you have seen recently.
Dennis Coon
Answers: 1. F 2. accommodation (M), convergence (B), retinal disparity
(B), linear perspective (M), motion parallax (M), overlap (M), relative size
(M) 3. accommodation or convergence 4. F 5. a 6. An artist must transfer
a three-dimensional scene onto a flat canvas. Because Rembrandt could
not see depth, it might have been easier for him to put what he saw onto
a two-dimensional surface.
Figure 5.21 Before you can use familiar size to judge distance, objects must
•actually
be the size you assume they are. Either these men are giants, or the model
airplane was closer than you may have thought when you looked at • Figure 5.16.
To what extent has the apparent-distance hypothesis been confirmed? The father and son team of Lloyd and James Kaufman
projected images of the moon on a mirror. This allowed them to
superimpose an artificial moon on the sky. In addition, the mirrors were moveable. Volunteer observers reported that as the
moon moved closer, it appeared to get smaller. This effect was
most dramatic when the moon was near the horizon, where
more depth cues are found. This is the strongest confirmation
yet of the apparent-distance theory (Kaufman & Kaufman,
2000).
Perceptual Learning — What if
the World Were Upside Down?
Gateway Question: What effect does learning have on perception?
England is one of the few countries in the world where people
drive on the left side of the road. Because of this reversal, it is not
unusual for visitors to step off curbs in front of cars — after carefully looking for traffic in the wrong direction. As this example
suggests, learning has a powerful impact on top-down processing
in perception.
Moon illusion The apparent change in size that occurs as the moon
moves from the horizon (large moon) to overhead (small moon).
Apparent-distance hypothesis An explanation of the moon illusion
stating that the horizon seems more distant than the night sky.
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Perceptual Habits
In general, learning creates perceptual habits (ingrained patterns of
organization and attention) that affect our daily experience. Stop for
a moment and look at Figure 5.23. The left face looks somewhat
unusual, to be sure. But the distortion seems mild—until you turn
the page upside down. Viewed normally, the face looks quite grotesque. Why is there a difference? Apparently, most people have little
experience with upside-down faces. Perceptual learning, therefore,
has less impact on our perceptions of an upside-down face. With a
face in the normal position, you know what to expect and where to
look. Also, you tend to see the entire face as a recognizable pattern.
When a face is inverted, we are forced to perceive its individual features separately (Caharel et al., 2006).
Top-down perceptual processing habits can easily lead our perceptions astray. Because we have seen thousands of rooms shaped
roughly like a box, we habitually construct perceptions based on
this assumption. This need not be true, however. An Ames room
(named for the man who designed it) is a lopsided space that
appears square when viewed from a certain point ( Figure 5.24).
•
(b)
(c)
How does learning affect perception? The term perceptual learning refers to changes in the brain that alter how we construct sensory information into percepts (Fahle & Poggio, 2002). For example, to use a computer, you must learn to pay attention to specific
stimuli, such as icons and cursors. We also learn to tell the difference between stimuli that seemed identical at first. An example is
the novice chef who discovers how to tell the difference between
dried basil, oregano, and tarragon. In other situations, we learn to
focus on just one part of a group of stimuli. This saves us from having to process all the stimuli in the group. For instance, a linebacker
in football may be able to tell if the next play will be a run or a pass
by watching one or two key players, rather than the
entire opposing team (Seitz & Watanabe, 2005).
Even something as simple as figure-ground perception is affected by learning. For example, if you
cut a shape out of dark paper and place it on a white
background, other people are more likely to see it as
a figure if it resembles a familiar object. As another
example, in Figure 5.22a you can probably shift
between seeing the white shape or the black shape as
an object. Now look at Figure 5.22b. Does the
lower black shape seem more like it’s the figure than
the upper white shape? Next consider Figure 5.22c.
Notice how the white area in Figure 5.22c seems
like it has become the figure. In our daily experience,
objects below the horizon are usually closer to us.
Also, we typically see more objects below the horizon
than above it. Because of such experiences, we are
more likely to perceive areas below the “horizon” line
in a drawing as objects or figures (Vecera, Vogel, &
Woodman, 2002). Does this mean you figure that
Figure 5.23 The effects of prior experience on perception. The doctored face looks far worse
when viewed right side up because it can be related to past experience.
figures are close to the ground?
•
•
•
•
•
•
•
Figure 5.24 The Ames room.
From the front, the room looks normal;
actually, the right-hand corner is very
short, and the left-hand corner is very
tall. In addition, the left side of the room
slants away from viewers. The diagram
shows the shape of the room and reveals
why people appear to get bigger as
they cross the room toward the nearer,
shorter right corner.
Mark McKenna
Peephole
Bettmann/Corbis
•
(a)
Figure 5.22
Perceiving the World
167
HU M AN D I VERS I T Y
Do They See What We See?
According to psychologist Richard Nisbett
and his colleagues, people from different
cultures do, in fact, perceive the world differently. European Americans are individualistic
people who tend to focus on themselves and
their sense of personal control. In contrast,
East Asians are collectivist people who tend to
focus on their personal relationships and social
responsibilities. As a consequence, European
Americans tend to explain actions in terms of
internal factors (“she did it because she chose
to do it”). In comparison, East Asians tend to
explain actions in terms of their social context
(“he did it because it was his responsibility to
his family”) (Norenzayan & Nisbett, 2000).
Do such cultural differences affect our
everyday perception of objects and events?
Apparently they do. In one study, American
and Japanese participants were shown drawings of everyday scenes, such as a farm. Later,
they saw a slightly changed version of the
scene. Some of the changes were made to
the focal point, or figure of the scene. Other
changes altered the surrounding context, or
ground of the scene. Americans, it turns out,
were better at detecting changes in the figure
of a scene. Japanese participants were better at finding alterations in the background
(Nisbett & Miyamoto, 2005).
This illusion is achieved by carefully distorting the proportions of
the walls, floor, ceiling, and windows. Because the left corner of
the Ames room is farther from a viewer than the right, a person
standing in that corner looks very small; one standing in the
nearer, shorter right corner looks very large. A person who walks
from the left to the right corner, will seem to “magically” grow
larger.
Before we continue, read aloud the short phrase in Figure 5.25.
Did you read, “Paris in the spring”? If so, look again. The word the
appears twice in the phrase. Because of past experience with the
English language, good readers often overlook the repeated word.
Again, the effects of perceptual learning are apparent. (Now you
know why it is easy to miss spelling mistakes while proofreading
your essays.)
As mentioned in Chapter 4, the brain is especially sensitive to
perceptual features such as lines, shapes, edges, spots, and colors.
At least some of this sensitivity appears to be learned. Colin Blakemore and Graham Cooper raised kittens in a room with only vertical stripes on the walls. Another set of kittens saw only horizontal
stripes. When returned to normal environments, the “horizontal”
cats could easily jump onto a chair, but when walking on the floor,
they bumped into chair legs. “Vertical” cats, on
the other hand, easily avoided chair legs, but
they missed when trying to jump to horizontal surfaces. The cats raised with vertical stripes were “blind” to horizontal
lines, and the “horizontal” cats acted
Paris
as if vertical lines were invisible. In
in the
such cases, there is an actual
the spring
decrease in brain cells tuned to
the missing features (Blakemore
Figure 5.25
& Cooper, 1970).
•
•
To explain this difference, Chua, Boland,
and Nisbett (2005) presented American
and Chinese participants with pictures of a
figure (such as a tiger) placed on a ground
(such as a jungle) and monitored their
eye-movement patterns. The Americans
focused their eye movements on the figure; Chinese participants made more eye
movements around the ground. In other
words, Westerners have a relatively narrow
focus of attention, whereas Easterners have
a broader focus of attention. Apparently,
the society we live in can, indeed, influence
even our most basic perceptual habits.
Perceptual features might seem removed from daily experience.
Nevertheless, they can have a profound effect on human behavior.
In recognizing faces, for example, a consistent other-race effect
occurs. This is a sort of “they all look alike to me” bias in perceiving persons from other racial and ethnic groups. In tests of facial
recognition, people are much better at recognizing faces of their
own race than others. One reason for this difference is that we
typically have more experience with people from our own race. As
a result, we become very familiar with the features that help us
recognize different persons. For other groups, we lack the perceptual expertise needed to accurately separate one face from another
(Sporer, 2001). Okay, so maybe members of different races or ethnic groups have developed perceptual habits that lead them to see
in-group faces differently, but we all see everything else the same,
right? For an answer, see “Do They See What We See?”
Inverted Vision
Would it be possible for an adult to adapt to a completely new perceptual world? An answer comes from an experiment in which a person wore goggles that turned the world upside down and reversed
objects from right to left. At first, even the simplest tasks — walking, eating, and so forth — were incredibly difficult. Imagine trying to reach for a door handle and watching your hand shoot off
in the wrong direction.
Perceptual learning Changes in how we construct sensory
information into percepts that can be attributed to prior experience.
Perceptual habits Well-established patterns of perceptual organization
and attention.
Perceptual features Important elements of a stimulus pattern, such as
lines, shapes, edges, spots, and colors.
CHAPTER 5
David Young-Wolff/PhotoEdit
168
• Figure 5.26 Are the center dots in both figures the same size?
Inverted vision. Adaptation to complete inversion of the visual world is possible,
but challenging.
Participants in the experiment also reported that head movements made the world swing violently through space, causing
severe headaches and nausea. Yet after several days they began to
adapt to inverted vision. Their success, although not complete,
was impressive.
Did everything turn upright again for the humans? No. While
they wore the goggles, their visual images remained upside down.
But in time they learned to perform most routine activities, and
their inverted world began to seem relatively normal. In later
experiments, some people wearing inverting lenses were able to
successfully drive cars. One person even flew an airplane (Kohler,
1962). These feats are like driving or flying upside down, with
right and left reversed. Some ride!
Interacting with a new visual world through active movement
(self-generated action) seems to be a key to rapid adaptation. In
one experiment, people wore glasses that grossly distorted vision.
Those who walked on their own adapted more quickly than persons pushed around in a wheeled cart (Held, 1971). Why does
movement help? Probably because commands sent to the muscles
can be related to sensory feedback. Remaining immobile would be
like watching a weird movie over which you have no control.
There would be less reason for any perceptual learning to occur.
The Context of Perception
The external context in which a stimulus is judged is an important
factor affecting perception. Context refers to information surrounding a stimulus. For example, a man 6 feet in height will look
“tall” when surrounded by others of average height, and “short”
among a group of professional basketball players. In Figure 5.26,
the center circle is the same size in both designs. But like the man
in different company, context alters the circle’s apparent size. The
importance of context is also shown by Figure 5.27. What do
you see in the middle? If you read across, context causes it to be
organized as a 13. Reading down makes it a B.
•
•
• Figure 5.27 Context alters the meaning of the middle figure.
Illusions
Perceptual learning is responsible for a number of illusions. In an
illusion, length, position, motion, curvature, or direction is consistently misjudged. Note that illusions are distorted perceptual
constructions of stimuli that actually exist. In a hallucination,
people perceive objects or events that have no external reality
(Lepore, 2002). For example, they hear voices that are not there.
(See “Staying in Touch with Reality.”) Illusions and hallucinations
can be distinguished by reality testing.
What do you mean by reality testing? In any situation having
an element of doubt or uncertainty, reality testing involves
obtaining additional information to check your perceptions. If
you think you see a 3-foot-tall butterfly, you can confirm you are
hallucinating by trying to touch its wings. To detect an illusion,
you may have to measure a drawing or apply a straightedge to it.
Figure 5.28 shows a powerful illusion called Fraser’s spiral.
What appears to be a spiral is actually made up of a series of
closed circles. Most people cannot spontaneously see this reality.
Instead, they must carefully trace one of the circles to confirm
what is “real” in the design.
•
169
Perceiving the World
T HE CLI N I CA L FI LE
Staying in Touch with Reality
Even though Nash suffered from schizophrenia, he eventually learned to use his ability to
engage in reality testing to sort out which of
his experiences were perceptions and which
were hallucinations. Unlike John Nash, most
people who experience full-blown hallucinations also have a limited ability to reality test
(Hohwy & Rosenberg, 2005).
Curiously, “sane hallucinations” also
occur. Charles Bonnet syndrome is a rare
condition that afflicts mainly older people
who are partially blind but not mentally
disturbed. They may “see” people, animals,
buildings, plants, and other objects appear
and disappear in front of their eyes. One
older man suffering from partial blindness
and leukemia complained of seeing animals in his house, including cattle and bears
(Jacob et al., 2004). However, people experiencing “sane hallucinations” can more easily tell that their hallucinations aren’t real
because their capacity to reality test is not
impaired.
Such unusual experiences show how powerfully the brain seeks meaningful patterns
in sensory input and the role reality testing
plays in our normal perceptual experience.
Dennis Coon
Just imagine that often, and without warning, you hear a voice shouting, “Buckets of
blood!” or see blood spattering across the
walls of your bedroom. Chances are people
would think you are mentally disturbed.
Hallucinations are a major symptom of
psychosis, dementia, epilepsy, migraine
headaches, alcohol withdrawal, and drug
intoxication (Spence & David, 2004) and are
one of the clearest signs that a person has
“lost touch with reality.”
Yet consider the case of mathematician
John Nash (the subject of A Beautiful Mind,
the winner of the 2002 Oscar for best film).
Illusions are a fascinating challenge to our understanding of
perception. On occasion, they also have practical uses. An illusion
called stroboscopic (strobe-oh-SKOP-ik) movement puts the
“motion” in motion pictures. Stroboscopic movement refers to
the illusory motion perceived when objects are shown in rapidly
changing positions. The strobe lights used on dance floors reverse
this illusion. Each time the strobe flashes, it “freezes” dancers in
particular positions. However, if the light flashes fast enough,
normal motion is seen. In a similar way, movies project a rapid
series of “snapshots,” so the gaps in motion are imperceptible.
Context Information surrounding a stimulus.
Illusion A misleading or distorted perception.
Hallucination An imaginary sensation, such as seeing, hearing, or
smelling something that does not exist in the external world.
Figure 5.28 The limits of pure perception. Even simple designs are easily
•misperceived.
Fraser’s spiral is actually a series of concentric circles. The illusion is so
Reality testing Obtaining additional information to check on the
accuracy of perceptions.
powerful that people who try to trace one of the circles sometimes follow the illusory spiral and jump from one circle to the next. (After Seckel, 2000.)
Stroboscopic movement Illusion of movement in which an object is
shown in a rapidly changing series of positions.
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CHAPTER 5
(a) Which of the horizontal
lines is longer?
(b) Is the diagonal a single
straight line? Check it with
a ruler.
(c) Is this a drawing of a staircase descending from upper
left to lower right . . . or is it
the view of the underneath of
a staircase from lower right to
upper left?
(d) Are these lines parallel?
Cover some of the slash
marks to see.
(e) Which line is longer,
horizontal or vertical?
(f) Notice how the background
distorts the square.
(g) Which quadrilateral is
larger?
(h) Which column is
shortest? Which is
longest?
• Figure 5.29 Some interesting perceptual illusions. Such illusions are a normal part of visual perception.
Can other illusions be explained? Not in all cases, or to everyone’s satisfaction. Generally speaking, size and shape constancy,
habitual eye movements, continuity, and perceptual habits combine in various ways to produce the illusions in Figure 5.29.
Rather than attempt to explain all the pictured illusions, let’s focus
on one deceptively simple example.
Consider the drawing in Figure 5.29a. This is the familiar
Müller-Lyer (MEOO-ler-LIE-er) illusion, in which the horizontal line with arrowheads appears shorter than the line with Vs. A
•
•
•
Figure 5.30 Why does line (b) in the Müller-Lyer illusion look longer than line (a)? Probably because it looks more
like a distant corner than a nearer one. Because the vertical
lines form images of the same length, the more “distant” line
must be perceived as larger. As you can see in the drawing on
the right, additional depth cues accentuate the Müller-Lyer
illusion. (After Enns & Coren, 1995.)
(a)
(b)
quick measurement will show that they are the same length. How
can we explain this illusion? Evidence suggests it is based on a
lifetime of experience with the edges and corners of rooms and
buildings. Richard Gregory (2000) believes you see the horizontal
line with the Vs as if it were the corner of a room viewed from
inside ( Figure 5.30). The line with arrowheads, on the other
hand, suggests the corner of a room or building seen from outside.
In other words, cues that suggest a 3-D space alter our perception
of a 2-D design (Enns & Coren, 1995).
•
Perceiving the World
View I
View II
171
View III
Figure 5.31 “Young woman/old woman” illustrations. As an interesting demonstration of perceptual expectancy, show some of your
•friends
view I and some view II (cover all other views). Next show your friends view III and ask them what they see. Those who saw view I should
see the old woman in view III; those who saw view II should see the young woman in view III. Can you see both? (After Leeper, 1935.)
Earlier, to explain the moon illusion, we said that if two objects
make images of the same size, the more distant object must be
larger. This is known formally as size-distance invariance (the
size of an object’s image is precisely related to its distance from the
eyes). Gregory believes the same concept explains the Müller-Lyer
illusion. If the V-tipped line looks farther away than the arrowheadtipped line, you must compensate by seeing the V-tipped line as
longer. This explanation presumes that you have had years of experience with straight lines, sharp edges, and corners — a pretty safe
assumption in our culture.
Is there any way to show that past experience causes the illusion? If
we could test someone who saw only curves and wavy lines as a
child, we would know if experience with a “square” culture is
important. Fortunately, the Zulus, a group of people in South
Africa, live in a “round” culture. In their daily lives, Zulus rarely
encounter a straight line: Their houses are shaped like rounded
mounds and arranged in a circle, tools and toys are curved, and
there are few straight roads or square buildings.
What happens if a Zulu looks at the Müller-Lyer design? The
typical Zulu villager does not experience the illusion. At most, she
or he sees the V-shaped line as slightly longer than the other
(Gregory, 1990). This seems to confirm the importance of past
experience and perceptual habits in determining our view of the
world. But, like many topics in psychology, room for debate
remains. The Müller-Lyer illusion also seems to be partly based on
directly misperceiving the location of the ends of the lines (Morgan, Hole, & Glennerster, 1990). Thus, it could be that both
apparent size and misperception cause the illusion.
Perceptual Expectancies —
On Your Mark, Get Set
Gateway Question: To what extent do we see what we expect to see?
An excellent example of how top-down processing influences our
experiences is found in perceptual expectancies.
What is a perceptual expectancy? A runner in the starting blocks
at a track meet is set to respond in a certain way. Likewise, past experience, motives, context, or suggestions may create a perceptual
expectancy (or set) that prepares you to perceive in a certain way. If
a car backfires, runners at a track meet may jump the gun. As a matter of fact, we all frequently jump the gun when perceiving. Beginning artists are notoriously bad at drawing faces. Why? When drawing a face, a novice tends to think “nose, mouth, eyes, ears” and tries
to draw what he or she thinks each of these features looks like,
instead of what they actually look like (Cohen & Bennett, 1997). In
essence, an expectancy is a perceptual hypothesis we are very likely to
apply to a stimulus—even if applying it is inappropriate.
Perceptual sets often lead us to see what we expect to see. For
example, let’s say you are driving across the desert. You are very low
on gas. Finally, you see a sign approaching. On it are the words
FUEL AHEAD. You relax, knowing you will not be stranded. But
as you draw nearer, the words on the sign become FOOD AHEAD.
Most people have had similar experiences in which expectations
altered their perceptions. To observe perceptual expectancies firsthand, perform the demonstration described in Figure 5.31.
Perceptual expectancies are frequently created by suggestion. In
one study (wine snobs take note), participants given a taste of a
$90 wine reported that it tasted better than a $10 wine. Functional MRI images confirmed that brain areas related to pleasure
were indeed more active when participants tasted the more expensive wine (Plassmann et al., 2008). The twist is that exactly the
same wine was served in both cases. Merely suggesting that the
•
Müller-Lyer illusion Two equal-length lines tipped with inward or
outward pointing Vs appear to be of different lengths.
Size-distance invariance The strict relationship between the distance
an object lies from the eyes and the size of its image.
Perceptual expectancy (or set) A readiness to perceive in a particular
manner, induced by strong expectations.
CHAPTER 5
wine was expensive created a perceptual expectancy that it would
taste better. And so it did (advertisers also take note).
Does it really make that much difference what you call someone or
something? Perceptual categories, especially those defined by labels,
do make a difference. This is especially true in perceiving people,
where even trained observers may be influenced. For example, in
one study, psychotherapists were shown a videotaped interview.
Half the therapists were told that the man being interviewed was
applying for a job. The rest were told that the man was a mental
patient. Therapists who thought the man was a job applicant perceived him as “realistic,” “sincere,” and “pleasant.” Those who
thought he was a patient perceived him as “defensive,” “dependent,” and “impulsive” (Langer & Abelson, 1974).
In the next section, we will go beyond normal perception to
ask, “Is extrasensory perception possible?” Before we do that,
here’s a chance to answer the question, “Is remembering the preceding discussion possible?”
K NOW LED GE B U I L D E R
Perceptual Learning and Expectancies
RECITE
1. Perceptual habits may become so ingrained that they lead us to
misperceive a stimulus. T or F?
2. The Ames room is used to test for adaptation to inverted vision.
T or F?
3. Perceptual learning seems to program the brain for sensitivity to
important __________________________ of the environment.
4. An important factor in adaptation to inverted vision is
a. learning new categories
b. active movement
c. overcoming illusions
d. the horizontal-vertical invariance
5. Reality testing can be used to distinguish hallucinations and illusions. T or F?
6. Size-distance relationships appear to underlie which two illusions?
_______________________ and ______________________________
7. When a person is prepared to perceive events in a particular way, it is
said that a perceptual expectancy or ____________________ exists.
REFLECT
Critical Thinking
8. What size object do you think you would have to hold at arm’s
length to cover up a full moon?
Relate
How has perceptual learning affected your ability to safely drive a car?
For example, what do you pay attention to at intersections? Where do
you habitually look as you are driving?
If you spent a year hiking the Amazon River Basin, what effect might it
have on your perception of the Müller-Lyer illusion?
You have almost certainly misperceived a situation at some time
because of a perceptual expectancy. How were your perceptions
influenced?
Extrasensory Perception —
Do You Believe in Magic?
Gateway Question: Is extrasensory perception possible?
About half the general public believes in the existence of extrasensory perception (ESP) — the purported ability to perceive
events in ways that cannot be explained by known sensory
capacities (Wiseman & Watt, 2006). Actually, it’s surprising
that even more people aren’t believers. ESP and other paranormal events are treated as accepted facts in many movies and
television programs. Regardless, very few psychologists share
this belief. What is the evidence for and against extrasensory
perception?
Parapsychology is the study of ESP and other psi phenomena (events that seem to defy accepted scientific laws). (Psi is
pronounced like “sigh.”) Parapsychologists seek answers to
the questions raised by three basic forms that ESP could take.
These are:
1. Telepathy. The purported ability to communicate directly
with another person’s mind. When the other person is dead,
the communications are called mediumship.
2. Clairvoyance. The purported ability to perceive events or
gain information in ways that appear unaffected by distance
or normal physical barriers.
3. Precognition. The purported ability to perceive or accurately predict future events. Precognition may take the form
of prophetic dreams that foretell the future.
While we are at it, we might as well toss in another purported psi
ability:
4. Psychokinesis. The purported ability to exert influence
over inanimate objects by willpower (“mind over matter”).
(Psychokinesis cannot be classed as a type of ESP, but it is
frequently studied by parapsychologists.)
The formal investigation of psi events owes much to the late
J. B. Rhine, who tried to study ESP objectively. Many of Rhine’s
experiments made use of Zener cards (a deck of 25 cards, each
bearing one of five symbols) ( Figure 5.32). In a typical clairvoyance test, people try to guess the symbols on the cards as they are
turned up from a shuffled deck. In a typical telepathy test, a
receiver tries to guess the correct symbol by reading the mind of a
sender looking at a card. Pure guessing in these tests will produce
an average score of 5 “hits” out of 25 cards.
•
+
172
Figure 5.32 ESP cards used by J. B. Rhine, an early experi•menter
in parapsychology.
Answers: 1. T 2. F 3. features 4. b 5. T 6. moon illusion, Müller-Lyer illusion 7. set 8. The most popular answers range from a quarter to a softball. Actually, a pea held in the outstretched hand will cover a full moon
(Kunkel, 1993). If you listed an object larger than a pea, be aware that
perceptions, no matter how accurate they seem, may distort reality.
Perceiving the World
An Appraisal of ESP
Psychologists as a group are highly skeptical about psi abilities. If
you’ve ever had an apparent clairvoyant or telepathic experience
you might be convinced that ESP exists. However, the difficulty of
excluding coincidence makes such experiences less conclusive than
they might seem. Consider a typical “psychic” experience: During
the middle of the night, a woman away for a weekend visit suddenly
had a strong impulse to return home. When she arrived she found
the house on fire with her husband asleep inside (Rhine, 1953). An
experience like this is certainly striking, but it does not confirm the
reality of ESP. You may not realize it, but such coincidences occur
quite often. On any given night, many, many people might act on a
“premonition.” If, by coincidence, one person’s hunch turns out to
be correct, it may be reinterpreted as precognition or clairvoyance
(Marks, 2000; Wiseman & Watt, 2006). In contrast, the vast
majority of false premonitions will simply be forgotten.
Fraud and Skepticism
Unfortunately, some of Rhine’s most dramatic early experiments
used badly printed Zener cards that allowed the symbols to show
faintly on the back. It is also very easy to cheat, by marking cards
with a fingernail or by noting marks on the cards caused by normal
use. Even if this were not the case, there is evidence that early experimenters sometimes unconsciously gave people cues about cards
with their eyes, facial gestures, or lip movements. In short, none of
173
the early studies in parapsychology were done in a way that eliminated the possibility of deliberate fraud or the accidental “leakage”
of helpful information (Alcock, Burns, & Freeman, 2003).
Modern parapsychologists are now well aware of the need for
double-blind experiments, security and accuracy in record keeping, meticulous control, and repeatability of experiments (Milton
& Wiseman, 1997; O’Keeffe & Wiseman, 2005). In the last
10 years, hundreds of experiments have been reported in parapsychological journals. Many of them seem to support the existence
of psi abilities.
Then why do most psychologists remain skeptical about psi abilities? For one thing, fraud continues to plague the field. The need
for skepticism is especially great anytime there’s money to be made
from purported psychic abilities. For example, the owners of the
“Miss Cleo” TV-psychic operation were convicted of felony fraud
in 2002. “Miss Cleo,” supposedly a Jamaican psychic, was really
just an actress from Los Angeles. People who paid $4.99 a minute
for a “reading” from “Miss Cleo” actually reached one of several
hundred operators. These people were hired through ads that
read, “No experience necessary.” Despite being entirely faked, the
“Miss Cleo” scam brought in more than $1 billion before it was
shut down.
Anyone can learn to do “cold readings” (Wood et al., 2003)
well enough to produce satisfied customers. Cold reading is a set of
techniques that are used to lead people to believe in the truth of
what a psychic or medium is saying about them. These include a
reliance on many of the same techniques used by practitioners of
the horoscope, such as uncritical acceptance, positive instances,
and the Barnum effect. (Remember Chapter 1, pages 18–19?)
The “psychic” begins a “reading” by making general statements
about a person. The “psychic” then plays “hot and cold” by attending to the person’s facial expressions, body language, or tone of voice.
When the “psychic” is “hot” (on the right track), the “psychic” continues to make similar statements about the person. If the person’s
reactions signal that the “psychic” is “cold,” the psychic drops that
topic or line of thought and tries another (Hyman, 2007).
© Kes/www.CartoonStock.com
Extrasensory perception The purported ability to perceive events
in ways that cannot be explained by known capacities of the sensory
organs.
Parapsychology The study of extranormal psychological events, such
as extrasensory perception.
Psi phenomena Events that seem to lie outside the realm of accepted
scientific laws.
Telepathy The purported ability to directly know another person’s
thoughts.
Clairvoyance The purported ability to perceive events at a distance or
through physical barriers.
Precognition The purported ability to accurately predict future events.
Psychokinesis The purported ability to mentally alter or influence
objects or events.
Zener cards A deck of 25 cards bearing various symbols and used in
early parapsychological research.
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CHAPTER 5
results of flipping the coin. Does this mean that the person, for a
time, had precognition — then lost it? Parapsychologists tend to
believe the answer is yes. Skeptics assume that nothing more than
random matching occurred, as in the two-coin example.
Reinterpretation is also a problem in psi experiments. For
example, ex-astronaut Edgar Mitchell claimed he did a successful
telepathy experiment from space. Yet news accounts never mentioned that on some trials Mitchell’s “receivers” scored above
chance, whereas on others they scored below chance. Although
you might assume that below-chance trials were failures to find
telepathy, Mitchell reinterpreted them as “successes,” claiming that
they represented intentional “psi missing.” But, as skeptics have
noted, if both high scores and low scores count as successes, how
can you lose?
Of course, in many ESP tests the outcome is beyond debate. A
good example is provided by ESP experiments done through
newspapers, radio, and television. In these mass media studies,
people attempted to identify ESP targets from a distance. The
results of more than 1.5 million ESP trials done through the mass
media are easy to summarize: There was no significant ESP effect
(Milton & Wiseman, 1999). Zero. Zip. Nada. Clearly, state lottery
organizers have nothing to fear!
Inconclusive Results, Statistics and Chance
Inconsistency is another major problem in psi research. For
every study with positive results, there are many others that fail
and are never published (Alcock, 2003). Unfortunately, many
of the most spectacular findings in parapsychology simply cannot be replicated (reproduced or repeated) (Hyman, 1996a).
More important, improved research methods usually result in
fewer positive results (Hyman, 1996b; O’Keeffe & Wiseman,
2005).
Even the same researchers using the same experimental subjects typically can’t get similar results every time (Schick &
Vaughn, 2001). It is rare — in fact, almost unheard of — for a person to maintain psi ability over any sustained period (Alcock,
Burns, & Freeman, 2003). ESP researchers believe this “decline
effect” shows that parapsychological skills are very fragile. But
critics argue that a person who only temporarily scores above
chance has just received credit for a run of luck (a statistically
unusual outcome that could occur by chance alone). When the
run is over, it is not fair to assume that ESP is temporarily gone.
We must count all attempts.
To understand the run-of-luck criticism, imagine that you flip
a coin 100 times and record the results. You then flip another
coin 100 times, again recording the results. The two lists are
compared. For any 10 pairs of flips, we would expect heads or
tails to match 5 times. Let’s say that you go through the list and
find a set of 10 pairs where 9 out of 10 matched. This is far above
chance expectation. But does it mean that the first coin “knew”
what was going to come up on the second coin? The idea is obviously silly.
Now, what if a person guesses 100 times what will come up on
a coin. Again, we might find a set of 10 guesses that matches the
•
(a)
Figure 5.33
Stage ESP
If psychic phenomena do occur, they certainly can’t be controlled
well enough to be used by entertainers. Stage ESP simulates ESP
for the purpose of entertainment. Like stage magic, it is based on
sleight of hand, deception, and patented gadgets ( Figure 5.33).
A case in point is self-proclaimed “psychic,” Uri Geller, a former
nightclub magician who “astounded” audiences — and some scientists — with apparent telepathy, psychokinesis, and precognition.
•
(b)
(c)
Fake psychokinesis. (a) The performer shows an observer several straight keys. While doing so, he bends one of the keys
by placing its tip in the slot of another key. Normally, this is done out of sight, behind the “psychic’s” hand. It is clearly shown here so that you
can see how the deception occurs. (b) Next, the “psychic” places the two keys in the observer’s hand and closes it. By skillful manipulation, the
observer has been kept from seeing the bent key. The performer then “concentrates” on the keys to “bend them with psychic energy.” (c) The
bent key is revealed to the observer. “Miracle” accomplished! (Adapted from Randi, 1997.)
Perceiving the World
Implications
After close to 130 years of investigation, it is still impossible to say
conclusively whether psi events occur. As we have seen, a close
look at psi experiments often reveals serious problems of evidence,
procedure, and scientific rigor (Alcock, Burns, & Freeman, 2003;
Hyman, 2007; Stokes, 2001). The more closely psi experiments
are examined, the more likely it is that claimed successes will
evaporate (Alcock, 2003; Stokes, 2001). As one critic put it, positive ESP results usually mean “Error Some Place” (Marks, 2000).
Yet, being a skeptic does not mean a person is against something. It means that you are unconvinced. The purpose of this
discussion, then, has been to counter the uncritical acceptance of
psi events that is rampant in the media.
What would it take to scientifically demonstrate the existence of
ESP? Quite simply, a set of instructions that would allow any competent, unbiased observer to produce a psi event under standardized conditions that rule out any possibility of fraud (Schick &
Vaughn, 2001). As we mentioned in Chapter 1, professional magician and skeptic James Randi even offers a $1,000,000 prize to
anyone who can demonstrate evidence of psi events under standardized conditions. No one has yet claimed the prize. (You can
read all about it if you google the James Randi Educational Foundation.)
Undoubtedly, some intrepid researchers will continue their
attempts to supply just that. Others remain skeptics and consider
130 years of inconclusive efforts reason enough to abandon the
concept of ESP (Marks, 2000). At the least, it seems essential to be
carefully skeptical of evidence reported in the popular press or by
researchers who are uncritical “true believers.” (But then, you
already knew we were going to say that, didn’t you!)
A Look Ahead
In this chapter we have moved from basic sensations to the complexities of perceiving people and events. We have also probed
some of the controversies concerning ESP. In the Psychology in
Action section, we will return to “everyday” perception for a look
at perceptual awareness.
KNOWL E DG E B U I L DE R
Extrasensory Perception
RECITE
1. Four purported psi events investigated by parapsychologists are
clairvoyance, telepathy, precognition, and _____________________.
2. Zener cards were used in early studies of
a. psi phenomena
b. inattentional blindness
c. the Müller-Lyer illusion
d. top-down processing
3. Natural, or “real-life,” occurrences are regarded as the best evidence
for the existence of ESP. T or F?
4. Replication rates are very high for ESP experiments. T or F?
5. Skeptics attribute positive results in psi experiments to statistical
runs of luck. T or F?
REFLECT
Critical Thinking
6. What would you estimate is the chance that two people will have
the same birthday (day and month, but not year) in a group of 30
people?
7. A “psychic” on television offers to fix broken watches for viewers.
Moments later, dozens of viewers call the station to say that their
watches miraculously started running again. What have they overlooked?
Relate
Let’s say that a friend of yours is an avid fan of TV shows that feature paranormal themes. See if you can summarize for her or him what is known
about ESP. Be sure to include evidence for and against the existence of
ESP and some of the thinking errors associated with nonskeptical belief
in the paranormal.
Answers: 1. psychokinesis 2. a 3. F 4. F 5. T 6. Most people assume that
this would be a relatively rare event. Actually there is a 71 percent chance
that two people will share a birthday in a group of 30. Most people probably underestimate the natural rate of occurrence of many seemingly
mysterious coincidences (Alcock, Burns, & Freeman, 2003). 7. When psychologists handled watches awaiting repair at a store, 57 percent began
running again, with no help from a “psychic.” Believing the “psychic’s”
claim also overlooks the impact of big numbers: If the show reached
a large audience, at least a few “broken” watches would start working
merely by chance.
During testing, it seemed that Geller could sense which of 10 film
canisters contained a hidden object, he correctly guessed the number that would come up on a die shaken in a closed box, and he
reproduced drawings sealed in envelopes.
Was Geller cheating, or was he using some ability beyond normal
perception? There is little doubt that Geller was cheating (Randi,
1997). It’s now clear that tests of Geller’s performance were
incredibly sloppy. For instance, Geller reproduced sealed drawings
in a room next to the one where the drawings were made. Original
reports failed to mention that there was a hole in the wall between
the rooms, through which Geller could have heard descriptions of
the pictures as they were being drawn. Likewise, in the “die in the
box” tests Geller was allowed to hold the box, shake it, and have
the honor of opening it.
Why weren’t such details reported? Sensational and uncritical
reporting of apparent paranormal events is widespread. Hundreds
of books, articles, and television programs are produced each year
by people who are getting rich by promoting unsupported claims.
If a person did have psychic powers, he or she would not have to
make a living by entertaining others. A quick trip to a casino
would allow the person to retire for life.
175
Replicate To reproduce or repeat.
Run of luck A statistically unusual outcome (as in getting five heads in a
row when flipping a coin) that could still occur by chance alone.
Stage ESP The simulation of ESP for the purpose of entertainment.
176
CHAPTER 5
PSY C HO L O GY IN A CT ION
Perception and Objectivity — Believing Is Seeing
Gateway Question: How can I learn to
perceive events more accurately?
Have you ever seen the sun set? You may
think you have. Yet, in reality, we know the
sun does not “set.” Instead, our viewing angle
changes as the earth turns, until the sun is
obscured by the horizon. Want to try the
alternative? This evening, stand facing the
west. With practice, you can learn to feel
yourself being swept backward on the rotating surface of the earth as you watch an
unmoving sun recede in the distance.
This radical shift in perspective illustrates
the limitations of “objective” observation. As
we have learned in this chapter, seeing a “sunset” is a perceptual construction (mental model)
of an external event. As we have seen, perception reflects the needs, expectations, attitudes,
values, and beliefs of the perceiver. In this
light, the phrase “seeing is believing” must be
modified. Clearly, we see what we believe, as
well as believe what we see ( Figure 5.34).
In some cases, subjective perception nurtures the personal vision valued in art, music,
poetry, and scientific innovation. Often,
however, it is a real liability.
In the courtroom, eyewitness testimony can
be a key to proving guilt or innocence. The
claim “I saw it with my own eyes” still carries
a lot of weight with a jury. Too many jurors
(unless they have taken a psychology course)
tend to assume that eyewitness testimony is
nearly infallible (Durham & Dane, 1999).
Even U.S. judges are vulnerable to overoptimism about eyewitness testimony (Wise
& Safer, 2004). But, to put it bluntly, eyewitness testimony is frequently wrong (Wells &
Olson, 2003). Recall, for instance, that one of
your authors would have sworn in court that
he had seen a murder taking place at the
supermarket — if he hadn’t received more
information to correct his misperceptions.
bridges
Distortions in memory also affect the
accuracy of eyewitness testimony. See
Chapter 8, pages 256–259.
What about witnesses who are certain
that their perceptions were accurate? Should
juries believe them? Actually, having confidence in your testimony has almost no bearing on its accuracy (Brewer & Wells, 2006)!
Psychologists are gradually convincing lawyers, judges, and police that eyewitness errors
are common (Yarmey, 2003). Even so, thousands of people have been wrongfully convicted (Scheck, Neufeld, & Dwyer, 2000).
AP/Wide World Photo
•
Unfortunately, perception rarely provides
an “instant replay” of events. As stated earlier,
impressions formed when a person is surprised, threatened, or under stress are especially prone to distortion (Yuille & Daylen,
1998). In addition, being questioned tends to
make witnesses more confident about what
they saw, even if they are wrong. Thus, police
questioning can actually degrade the value of
the testimony witnesses give later, in court
(Shaw, 1996).
“I Saw It with My Own Eyes”
•
Figure 5.34 It is difficult to look at this simple
drawing without perceiving depth. Yet the drawing is
nothing more than a collection of flat shapes. Turn this
page counterclockwise 90 degrees and you will see
3 Cs, one within another. When the drawing is turned
sideways, it seems nearly flat. However, if you turn the
page upright again, a sense of depth will reappear.
Clearly, you have used your knowledge and expectations to construct an illusion of depth. The drawing
itself would only be a flat design if you didn’t invest it
with meaning.
Even in broad daylight, eyewitness testimony is
untrustworthy. In 2001 an American Airlines plane
crashed near Kennedy International Airport in New
York. Hundreds of people saw the plane go down.
Half of them said the plane was on fire. Flight recorders showed there was no fire. One witness in five saw
the plane make a right turn. An equal number saw
it make a left turn! As one investigator commented,
the best witness may be a “kid under 12 years old
who doesn’t have his parents around.” Adults, it
seems, are easily swayed by their expectations.
Because impressions formed when a person is surprised, threatened, or under stress
are especially prone to distortion, witnesses
to crimes often disagree. As a dramatic demonstration of this problem, a college professor
was attacked by an actor in a staged assault.
Immediately after the event, 141 witnesses
were questioned in detail. Their descriptions
were then compared with a videotape made
of the staged “crime.” The total accuracy score
for the group (on features such as appearance,
age, weight, and height of the assailant) was
only 25 percent of the maximum possible
(Buckhout, 1974). Similarly, a study of real
eyewitness cases found that the wrong person
was chosen from police lineups 25 percent of
the time (Levi, 1998).
Wouldn’t the victim of a crime remember
more than a mere witness? Not necessarily. A
revealing study found that eyewitness accuracy is virtually the same for witnessing a
crime (seeing a pocket calculator stolen) as it
is for being a victim (seeing one’s own watch
stolen) (Hosch & Cooper, 1982). Placing
more weight on the testimony of victims may
be a serious mistake. In many crimes, victims
fall prey to weapon focus. Understandably,
they fix their entire attention on the knife,
gun, or other weapon used by an attacker. In
doing so, they fail to notice details of appear-
Perceiving the World
Table 5.2
• Factors Affecting the Accuracy of Eyewitness Perceptions
Sources of Error
Summary of Findings
1. Wording of
questions
An eyewitness’s testimony about an event can be affected by how the questions put to that witness are worded.
2. Postevent
information
Eyewitness testimony about an event often reflects not only what was actually
seen but also information obtained later on.
3. Attitudes,
expectations
An eyewitness’s perception and memory of an event may be affected by his or
her attitudes and expectations.
4. Alcohol intoxication
Alcohol intoxication impairs later ability to recall events.
5. Cross-racial
perceptions
Eyewitnesses are better at identifying members of their own race than they
are at identifying people of other races.
6. Weapon focus
The presence of a weapon impairs an eyewitness’s ability to accurately identify
the culprit’s face.
7. Accuracyconfidence
An eyewitness’s confidence is not a good predictor of his or her accuracy.
8. Exposure time
The less time an eyewitness has to observe an event, the less well she or he
will perceive and remember it.
9. Unconscious
transference
Eyewitnesses sometimes identify as a culprit someone they have seen in
another situation or context.
10. Color
perception
Judgments of color made under monochromatic light (such as an orange
street light) are highly unreliable.
11. Stress
Very high levels of stress impair the accuracy of eyewitness perceptions.
Adapted from Kassin et al., 2001.
ance, dress, or other clues to identity (Pickel,
French, & Betts, 2003). Additional factors
that consistently lower eyewitness accuracy
are summarized in Table 5.2 (Kassin et al.,
2001; Wells & Olson, 2003).
•
Implications
Now that DNA testing is available, more
than 200 people who were convicted of murder, rape, and other crimes in the United
States have been exonerated. Most of these
innocent people were convicted mainly on
the basis of eyewitness testimony. Each also
spent years in prison before being cleared
(Foxhall, 2000). How often are everyday perceptions as inaccurate or distorted as those of
an emotional eyewitness? The answer we
have been moving toward is very frequently.
Bearing this in mind may help you be more
tolerant of the views of others and more cautious about your own objectivity. It may also
encourage more frequent reality testing on
your part.
Psychologist Sidney Jourard once offered
a good example of reality testing. One of
Jourard’s students believed her roommate
was stealing from her. The student gradually
became convinced of her roommate’s guilt
but said nothing. As her distrust and anger
grew, their relationship turned cold and distant. Finally, at Jourard’s urging, she confronted her roommate. The roommate
cleared herself immediately and expressed
relief when the puzzling change in their relationship was explained ( Jourard, 1974).
With their friendship reestablished, the true
culprit was soon caught. (The cleaning
woman did it!)
If you have ever concluded that someone
was angry, upset, or unfriendly without
checking the accuracy of your perceptions,
you have fallen into a subtle trap. Personal
objectivity is an elusive quality, requiring frequent reality testing to maintain. At the very
least, it pays to ask a person what she or he is
feeling when you are in doubt. Clearly, most
of us could learn to be better “eyewitnesses”
to daily events.
Positive Psychology:
Perceptual Awareness
Do some people perceive things more accurately than others? Humanistic psychologist
Abraham Maslow (1969) believed that some
people perceive themselves and others with
177
unusual accuracy. Maslow characterized
these people as especially alive, open, aware,
and mentally healthy. He found that their
perceptual styles were marked by immersion
in the present; a lack of self-consciousness;
freedom from selecting, criticizing, or evaluating; and a general “surrender” to experience. The kind of perception Maslow
described is like that of a mother with her
newborn infant, a child at Christmas, or two
people in love.
The Value of Paying Attention
Whereas the average person has not reached
perceptual restriction of the “if you’ve seen
one tree, you’ve seen them all” variety, the
fact remains that most of us tend to look at a
tree and classify it into the perceptual category of “trees in general” without really
appreciating the miracle standing before us.
How, then, can we bring about dishabituation (a reversal of habituation) on a day-today basis? Does perceptual clarity require
years of effort? Fortunately, a more immediate avenue is available. The deceptively simple key to dishabituation is this: Pay attention. The following story summarizes the
importance of attention:
One day a man of the people said to Zen Master
Ikkyu: “Master, will you please write for me some
maxims of the highest wisdom?”
Ikkyu immediately took his brush and wrote
the word “Attention.”
“Is that all?” asked the man. “Will you not add
something more?”
Ikkyu then wrote twice running: “Attention.
Attention.”
“Well,” remarked the man rather irritably, “I
really don’t see much depth or subtlety in what
you have just written.”
Then Ikkyu wrote the same word three times
running: “Attention. Attention. Attention.” Half
angered, the man demanded, “What does that
word ‘Attention’ mean anyway?”
And Ikkyu answered gently: “Attention
means attention.” (Kapleau, 1966)
To this we can add only one thought, provided by the words of poet William Blake: “If
the doors of perception were cleansed, man
would see everything as it is, infinite.”
Dishabituation A reversal of habituation.
CHAPTER 5
How to Become a Better
“Eyewitness” to Life
Here’s a summary of ideas from this chapter
to help you maintain and enhance perceptual
awareness and accuracy.
1. Remember that perceptions are constructions of reality. Learn to regularly question your own perceptions. Are they
accurate? Could another interpretation
fit the facts? What assumptions are you
making? Could they be false? How
might your assumptions be distorting
your perceptions?
2. Break perceptual habits and interrupt
habituation. Each day, try to get away
from habitual, top-down processing
and do some activities in new ways. For
example, take different routes when you
travel to work or school. Do routines,
such as brushing your teeth or combing
your hair, with your nonpreferred hand.
Try to look at friends and family mem-
bers as if they are persons you just met
for the first time.
3. Seeking out-of-the-ordinary experiences.
The possibilities here range from trying
foods you don’t normally eat to reading
opinions very different from your own.
Experiences ranging from a quiet walk
in the woods to a trip to an amusement
park may be perceptually refreshing.
4. Beware of perceptual sets. Anytime you
pigeonhole people, objects, or events,
there is a danger that your perceptions
will be distorted by expectations or preexisting categories. Be especially wary of
labels and stereotypes. Try to see people
as individuals and events as unique, onetime occurrences.
5. Be aware of the ways in which motives
and emotions influence perceptions. It
is difficult to avoid being swayed by
your own interests, needs, desires, and
emotions. But be aware of this trap and
K NOW LED G E B U I L D E R
Perceptual Awareness and Accuracy
RECITE
1. Most perceptions can be described as active constructions of external reality. T or F?
2. Inaccuracies in eyewitness perceptions obviously occur in “real life,”
but they cannot be reproduced in psychology experiments. T or F?
3. Accuracy scores for facts provided by witnesses to staged crimes
may be as low as 25 percent correct. T or F?
4. Victims of crimes are more accurate eyewitnesses than are impartial
observers. T or F?
5. A good antidote to perceptual habituation can be found in conscious efforts to
a. reverse sensory gating
b. pay attention
c. achieve visual accommodation
d. counteract shape constancy
actively try to see the world through the
eyes of others. Taking the other person’s
perspective is especially valuable in disputes or arguments. Ask yourself, “How
does this look to her or him?”
6. Make a habit of engaging in reality
testing. Actively look for additional
evidence to check the accuracy of your
perceptions. Ask questions, seek clarifications, and find alternate channels of
information. Remember that perception
is not automatically accurate. You could
be wrong — we all are frequently.
7. Pay attention. Make a conscious effort to
pay attention to other people and your
surroundings. Don’t drift through life in
a haze. Listen to others with full concentration. Watch their facial expressions.
Make eye contact. Try to get in the habit
of approaching perception as if you are
going to have to testify later about what
you saw and heard.
REFLECT
Critical Thinking
6. Return for a moment to the incident described at the beginning of
this chapter. What perceptual factors were involved in the first version of the “murder”? How did the girl affect what was seen?
Relate
Because perceptions are constructions or models of external events, we
should all engage in more frequent reality testing. Can you think of a
recent event when a little reality testing would have saved you from misjudging a situation?
To improve your own perceptual awareness and accuracy, which
strategies would you emphasize first?
chapter in review
Answers: 1. T 2. F 3. T 4. F 5. b 6. The girl’s misperception, communicated so forcefully to one of your authors, created a powerful expectancy that influenced what he perceived. Also, the event happened
quickly (the exposure time was brief ), and the stressful or emotional
nature of the incident encouraged his own misperception.
178
Gateways to Perception
Perception is an active process of constructing sensations into a
meaningful mental representation of the world.
Attended sensations become part of the percept; motive and emotions influence attention.
• Perceptions are based on simultaneous bottom-up and topdown processing. Complete percepts are assembled out of
small sensory features in “bottom-up” fashion guided by
preexisting knowledge applied “top-down” to help organize
features into a meaningful whole.
• Attention is selective, and it may be divided among various
activities. Attention is closely related to stimulus intensity, repetition, contrast, change, and incongruity.
• The phenomenon called inattentional blindness suggests that
there can be no perception without attention.
Perceiving the World
179
• Attention is accompanied by an orientation response. When a
stimulus is repeated without change, the orientation response
undergoes habituation.
• Personal motives and values often alter perceptions by changing the evaluation of what is seen or by altering attention to
specific details.
Perceptual sets often lead us to perceive or misperceive what we
expect to see.
The Gestalt principles of organization bring order to our perceptions.
• Parapsychology is the study of purported psi phenomena,
including telepathy (as well as mediumship), clairvoyance, precognition, and psychokinesis.
• Research in parapsychology remains controversial owing to a
variety of problems and shortcomings.
• The more carefully controlled an ESP experiment is, the less
likely it is to produce evidence that ESP occurs.
• Stage ESP is based on deception and tricks.
• Separating figure and ground (object and background) is the
most basic perceptual organization.
• The following Gestalt principles also help organize sensations:
nearness, similarity, continuity, closure, contiguity, common
region, and combinations of the preceding.
• Basic elements of line drawings appear to be universally
recognized.
• Perceptual organization shifts for ambiguous stimuli.
Impossible figures resist stable organization altogether.
• A perceptual organization may be thought of as a hypothesis
held until evidence contradicts it.
Perceptual constancies allow us to find regularity in the constantly
changing energy patterns reaching our senses.
• In vision, the image projected on the retina is constantly
changing, but the external world appears stable and undistorted because of size, shape, and brightness constancy.
Various visual cues are used to construct the experience of depth.
• A basic, innate capacity for depth perception is present soon
after birth.
• Depth perception depends on binocular depth cues of retinal
disparity and convergence.
• Stereoscopic vision is created mainly by retinal disparity and
the resulting overlap and mismatch of visual sensations.
• Depth perception also depends on the monocular depth cue of
accommodation.
• Monocular “pictorial” depth cues also underlie depth perception. They are linear perspective, relative size, height in the
picture plane, light and shadow, overlap, texture gradients,
aerial haze, and motion parallax.
• The moon illusion can be explained by the apparent-distance
hypothesis, which emphasizes that many depth cues are present when the moon is near the horizon, and few are present
when it is overhead.
Perceptual learning influences the top-down organization and interpretation of sensations.
• Studies of inverted vision show that even the most basic organization is subject to a degree of change. Active movement
speeds adaptation to a new perceptual environment.
• Perceptual judgments are not made in a vacuum. They are
almost always related to context.
• One of the most familiar of all illusions, the Müller-Lyer illusion, seems to be related to perceptual learning, linear perspective, size-distance invariance relationships, and mislocating the
end points of the figure.
• Suggestion, motives, emotions, attention, and prior
experience combine in various ways to create perceptual
sets, or expectancies.
The bulk of the evidence to date is against the existence of ESP.
Awareness of the factors that can distort perception is the key to
improving perceptual accuracy.
• Perception is an active construction of events. This is one
reason why eyewitness testimony is surprisingly unreliable.
Eyewitness accuracy is further damaged by weapon focus and a
number of similar factors.
• Perceptual accuracy is enhanced by reality testing, dishabituation, and conscious efforts to pay attention.
• It is also valuable to break perceptual habits, to beware of perceptual sets, and to be aware of the ways in which motives and
emotions influence perceptions.
Web Resources
For an up-to-date list of direct links to interesting sites, including
those listed here, visit the student companion site for this book at
www.cengage.com/psychology/coon
Figure/Ground in Graphic Design Explore the use of the figureground principle in graphic design.
Gallery of Illusions An interesting and fun website that presents
illusory stimuli that are fun to view and that provides a basis to learn
about sensation and perception.
3-D Stereograms Find the 3-D images hidden in these pictures.
Perceptual Learning Explore an example of perceptual learning
through wine tasting.
James Randi Education Foundation Win $1,000,000 for proving,
under scientifically controlled conditions, that you have ESP.
The Innocence Project Read about real cases of people convicted
through eyewitness testimony but later exonerated by DNA evidence.
Avoiding Habituation Read about how advertisers apply the idea of
habituation to the design of advertisements.
180
CHAPTER 5
Interactive Learning
Introduction to Psychology: Gateways to Mind and Behavior Book
Companion Website
www.cengage.com/psychology/coon
Visit your book companion website, where you will find flash cards,
practice quizzes, web links, and more to help you study.
Just what you need to know NOW!
Spend time on what you need to master rather than on information you already have learned. Take a pre-test for this chapter, and
CengageNOW will generate a personalized study plan based on
your results. The study plan will identify the topics you need to
review and direct you to online resources to help you master those
topics. You can then take a post-test to help you determine the
concepts you have mastered and what you will need to work on.
Try it out! Go to www.cengage.com/login to sign in with an access
code or to purchase access to this product.
CHAPTER
6
States of Consciousness
Gateway Theme
Understanding states of consciousness can promote self-awareness and enhance
personal effectiveness.
Corbis/SuperStock
Gateway Questions
• What is an altered state of consciousness?
• What are the effects of sleep loss or changes in sleep
patterns?
•
•
•
•
•
•
Why do we sleep?
What are some sleep disorders and unusual sleep events?
Do dreams have meaning?
•
What is hypnosis?
Do meditation and sensory deprivation have any benefits?
What are the effects of the more commonly used
psychoactive drugs?
How can dreams be used to promote personal
understanding?
181
preview
A Visit to Several States (of Consciousness)
In Los Angeles, California, an aspiring actor consults a hypnotist for help in reducing her stage fright.
In the American Southwest, a Navajo elder gives his congregation peyote tea, a sacrament in the Native American Church,
as a drumbeat resounds in the darkness.
In Toronto, Canada, three businesswomen head for a popular
tavern after a particularly stressful day.
In Big Bend National Park in southern Texas, a college student
spends a day walking through the wilderness, in a quiet
state of mindfulness meditation.
In New Zealand, a Maori tohunga (priest) performs a nightlong
ritual to talk to the spirits who created the world in the
mythical period the Aborigines call Dreamtime.
In Northern Ireland, a nun living in a convent spends an entire
week in silent prayer and contemplation.
In Berkeley, California, an artist spends 2 hours in a flotation
chamber to clear her head before resuming work on a large
painting.
At a park in Amsterdam, a group of street musicians smoke a
joint and sing for spare change.
In Tucson, Arizona, one of your authors pours himself another
cup of coffee.
States of Consciousness —
The Many Faces of Awareness
instances, altered states have important cultural meanings. (See
“Consciousness and Culture” for more information.)
An unconscious person will die without constant care. Yet as
crucial as consciousness is, we can’t really explain how it occurs
(Robinson, 2008). Nevertheless, it is possible to identify various
states of consciousness and to explore the role they play in our
lives. Let’s begin with a look at the most common altered state,
sleep and dreaming.
Gateway Question: What is an altered state of consciousness?
To be conscious means to be aware. Consciousness consists of all
the sensations, perceptions, memories, and feelings you are aware
of at any instant (Koch, 2004). (See “What Is It Like to Be a Bat?”)
We spend most of our lives in waking consciousness, a state of
clear, organized alertness. In waking consciousness we perceive
times, places, and events as real, meaningful, and familiar. But
states of consciousness related to fatigue, delirium, hypnosis, drugs,
and euphoria may differ markedly from “normal” awareness.
Everyone experiences at least some altered states, such as sleep,
dreaming, and daydreaming (Blackmore, 2004). In everyday life,
changes in consciousness may also accompany long-distance running, listening to music, making love, or other circumstances.
Altered States of Consciousness
How are altered states distinguished from normal awareness? During
an altered state of consciousness (ASC), changes occur in the quality and pattern of mental activity. Typically there are distinct shifts
in our perceptions, emotions, memories, time sense, thoughts, feelings of self-control, and suggestibility (Siegel, 2005). Definitions
aside, most people know when they have experienced an ASC.
Are there other causes of ASCs? In addition to the ones mentioned, we could add: sensory overload (a rave, Mardi Gras crowd,
or mosh pit), monotonous stimulation (such as “highway hypnotism” on long drives), unusual physical conditions (high fever,
hyperventilation, dehydration, sleep loss, near-death experiences),
restricted sensory input, and many other possibilities. In some
182
Each of these people seeks to alter consciousness — in different ways, to different degrees, and for different reasons. As
these examples suggest, consciousness can take many forms.
In the discussion that follows, we will begin with the familiar
realms of sleep and dreaming and then move to more exotic
states of consciousness.
Sleep — A Nice Place to Visit
Gateway Question: What are the effects of sleep loss or changes in
sleep patterns?
Each of us will spend some 25 years of life asleep. Because sleep is
familiar, many people think they know all about it. But many
common-sense beliefs about sleep are false. For example, you are
not totally unresponsive during sleep. A sleeping mother may
ignore a jet thundering overhead but wake at the slightest whimper of her child. Likewise, you are more likely to awaken if you
hear your own name spoken, instead of another. It’s even possible
to do simple tasks while asleep. In one experiment, people learned
to avoid an electric shock by touching a switch each time a tone
sounded. Eventually, they could do it without waking. (This is
much like the basic survival skill of turning off your alarm clock
without waking.) Of course, sleep does impose limitations. Don’t
expect to learn math, a foreign language, or other complex skills
while asleep — especially if the snooze takes place in class (Froufe
& Schwartz, 2001). But do expect that a good sleep will help you
remember what you learned the day before (Fenn, Nusbaum, &
Margoliash, 2003; Saxvig et al., 2008).
States of Consciousness
183
CRIT ICA L T H I N KI N G
What Is It Like to Be a Bat?
Imagine hurtling through the air on leather
wings while shrieking noisily. Suddenly, the
faint echo of your own voice draws your
attention to a moth that is frantically trying
to evade you. You careen after it, twisting
through the pitch-black jungle. Dodging
trees and other bats, you catch the moth
and savor your first meal of the still-young
night.
In his famous essay, “What Is It Like to Be
a Bat?” Thomas Nagel (1974) points out that
we can learn a lot about bats from an objec-
tive, third-person point of view. Scientifically,
we know that bats use echolocation (they
emit sounds and interpret the echoes) to
hunt insects at night. But what does that
feel like from a subjective, first-person point
of view? Have you ever been curious about
what it is like to be a bat, or a dog, or a cat?
What runs through Rover’s mind when he
sniffs other dogs? Does Fluffy have dreams?
Are they as strange as ours? Do cats ever
worry about the future? Do they like music?
Do animals feel joy?
The Need for Sleep
sleep. However, The Guinness Book of Records no longer recognizes
sleep deprivation competitions because of possible health risks, so
Randy still holds the “official” record.)
What are the costs of sleep loss? At various times, Randy’s speech
was slurred, and he couldn’t concentrate, remember clearly, or
name common objects (Coren, 1996). Sleep loss also typically
causes trembling hands, drooping eyelids, inattention, irritability,
staring, increased pain sensitivity, and general discomfort (Doran,
Van Dongen, & Dinges, 2001).
Most people experience hypersomnia (hi-per-SOM-nee-ah:
excessive daytime sleepiness) after even a few hours of sleep loss.
Hypersomnia is a common problem during adolescence (Carskadon, Acebo, & Jenni, 2004). Rapid physical changes during
puberty increase the need for sleep. However, the quality and
quantity of sleep time tends to decrease during the teen years
(Fukuda & Ishihara, 2001).
Most people who have not slept for a day or two can still do
interesting or complex mental tasks. But they have trouble paying
attention, staying alert, and doing simple or boring routines (Belenky
et al., 2003). They are also susceptible to microsleeps, which are
brief shifts in brain activity to the pattern normally recorded during
How strong is the need for sleep? Sleep is an innate biological
rhythm that can never be entirely ignored (Lavie, 2001; Mistlberger, 2005). Of course, sleep will give way temporarily, especially
at times of great danger. As comedian and filmmaker Woody Allen
once put it, “The lion and the lamb shall lie down together, but
the lamb will not be very sleepy.” However, there are limits to how
long humans can go without sleep. A rare disease that prevents
sleep always ends with stupor, coma, and death (Dauvilliers et al.,
2004) ( Figure 6.1).
How long could a person go without sleep? With few exceptions,
4 days or more without sleep becomes hell for everyone. The
world record is held by Randy Gardner, who at age 17 went 264
hours (11 days) without sleep. Surprisingly, Randy needed only 14
hours of sleep to recover. As Randy found, most symptoms of
sleep deprivation (sleep loss) are reversed by a single night’s rest.
(In 2007, a man named Tony Wright went 266 hours without
Timothy Ross/The Image Works
•
•
Figure 6. 1 Not all animals sleep, but like humans, those that do have powerful sleep needs. For example, dolphins must voluntarily breathe air, which means
they face the choice of staying awake or drowning. The dolphin solves this problem
by sleeping on just one side of its brain at a time! The other half of the brain, which
remains awake, controls breathing (Jouvet, 1999).
According to Nagel, we cannot directly
know the first-person experience of animals
(or even other people, for that matter). The
difficulty of knowing other minds is why the
early behaviorists distrusted introspection.
(Remember Chapter 1?) A key challenge for
psychology is to use objective studies of the
brain and behavior to help us understand the
mind and consciousness, which are basically
private phenomena (Koch, 2004; Robinson,
2008).
Consciousness Mental awareness of sensations, perceptions,
memories, and feelings.
Waking consciousness A state of clear, organized alertness.
Altered state of consciousness (ASC) A condition of awareness
distinctly different in quality or pattern from waking consciousness.
Biological rhythm Any repeating cycle of biological activity, such as
sleep and waking cycles or changes in body temperature.
Sleep deprivation Being prevented from getting desired or needed
amounts of sleep.
Hypersomnia Excessive daytime sleepiness.
Microsleep A brief shift in brain-wave patterns to those of sleep.
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CHAPTER 6
HUM AN D IVERS I T Y
Throughout history, people have found ways
to alter consciousness (Siegel, 2005). A dramatic example is the sweat lodge ceremony
of the Sioux Indians. During the ritual, several
men sit in total darkness inside a small chamber heated by coals. Cedar smoke, bursts of
steam, and sage fill the air. The men chant
rhythmically. The heat builds. At last they can
stand it no more. The door is thrown open.
Cooling night breezes rush in. And then? The
cycle begins again — often to be repeated
four or five times more.
Like the yoga practices of Hindu mystics
or the dances of the Whirling Dervishes of
Turkey, the ritual “sweats” of the Sioux are
meant to cleanse the mind and body. When
they are especially intense, they bring altered
awareness and personal revelation.
People seek some altered states for pleasure, as is often true of drug intoxication. Yet
as the Sioux illustrate, many cultures regard
altered consciousness as a pathway to personal enlightenment. Indeed, all cultures
and most religions recognize and accept
some alterations of consciousness. However,
the meaning given to these states varies
greatly — from signs of “madness” and “possession” by spirits, to life-enhancing breakthroughs. Thus, cultural conditioning greatly
affects what altered states we recognize,
seek, consider normal, and attain (de Rios &
Grob, 2005).
sleep. Imagine placing an animal on a moving treadmill, over a pool
of water. Even under these conditions, animals soon drift into
repeated microsleeps. For a pilot or machine operator, this can spell
disaster (Hardaway & Gregory, 2005). If a task is monotonous (such
as factory work or air traffic control), no amount of sleep loss is safe.
In fact, if you lose just 1 hour of sleep a night, it can affect your
mood, memory, ability to pay attention, and even your health
(Maas, 1999). Sleep helps keep the brain healthy by regulating its
temperature, conserving energy, and aiding brain development and
repair. Biologically, sleep is a necessity, not a luxury.
When you drive, remember that microsleeps can lead to macroaccidents. Even if your eyes are open, you can fall asleep for a few
seconds. A hundred thousand crashes every year are caused by
sleepiness (Rau, 2005). Although coffee helps (Kamimori et al.,
2005), if you are struggling to stay awake while driving, you should
stop, quit fighting it, and take a short nap.
Severe sleep loss can cause a temporary sleep-deprivation psychosis (loss of contact with reality). Confusion, disorientation,
delusions, and hallucinations are typical of this reaction. Fortunately, such “crazy” behavior is uncommon. Hallucinations and
delusions rarely appear before 60 hours of wakefulness (Naitoh,
Kelly, & Englund, 1989).
How can I tell how much sleep I really need? Pick a day when you
feel well rested. Then sleep that night until you wake without an
alarm clock. If you feel rested when you wake up, that’s your natural sleep need. If you’re sleeping fewer hours than you need, you’re
building up a sleep debt (Maas, 1999).
Sleep Patterns
Sleep was described as an innate biological rhythm. What does that
mean? Daily sleep and waking periods create a variety of sleep patterns. Rhythms of sleep and waking are so steady that they con-
Expuesto-Nicolas Randall/Alamy
Consciousness and Culture
In many cultures, rituals of healing, prayer, purification, or personal transformation are accompanied by altered states of consciousness.
tinue for many days, even when clocks and light-dark cycles are
removed. However, under such conditions, humans eventually
shift to a sleep-waking cycle that averages slightly more than 24
hours (Czeisler et al., 1999) ( Figure 6.2). This suggests that
external time markers, especially light and dark, help tie our sleep
rhythms to days that are exactly 24 hours long. Otherwise, many
of us would drift into our own unusual sleep cycles (Duffy &
Wright, Jr., 2005).
•
bridges
Daily sleep cycles can be disrupted by rapid travel across
time zones (jet lag) and by shift work. See Chapter 10,
pages 322–323, for more information.
What is the normal range of sleep? A few rare individuals can get
by on an hour or two of sleep a night — and feel perfectly fine.
Only a small percentage of the population are short sleepers, averaging 5 hours of sleep or less per night. On the other end of the scale
we find long sleepers, who doze 9 hours or more (Grandner &
Kripke, 2004). The majority of us sleep on a familiar 7- to 8-hourper-night schedule. Urging everyone to sleep 8 hours would be like
advising everyone to wear medium-size shoes.
We need less sleep as we get older, right? Yes, total sleep time
declines throughout life. Those older than 50 average only 6 hours
of sleep a night. In contrast, infants spend up to 20 hours a day
sleeping, usually in 2- to 4-hour cycles. As they mature, most children go through a “nap” stage and eventually settle into a steady
cycle of sleeping once a day ( Figure 6.3). Perhaps we should all
continue to take an afternoon “siesta.” Midafternoon sleepiness is
a natural part of the sleep cycle. Brief, well-timed naps can help
•
States of Consciousness
(16 hours awake and 8 hours asleep). For instance, one study
showed that 28-hour “days” work for some people. Overall, sleep
patterns may be bent and stretched, but they rarely yield entirely
to human whims (Åkerstedt, 2007).
Time of Day
Noon
Midnight
Noon
Week
number
4
Unscheduled,
free-running
rhythm
5
Scheduled
light-dark
cycle
6
6.2 Sleep rhythms. Bars show periods of sleep during the fourth,
•fifth,Figure
and sixth weeks of an experiment with a human subject. During unscheduled
periods, the subject was allowed to select times of sleep and lighting. The result was
a sleep rhythm of about 25 hours. Notice how this free-running rhythm began to
advance around the clock as they fell asleep later each day. When periods of darkness (shaded area) were imposed during the fifth week, the rhythm quickly resynchronized with 24-hour days. (Adapted from Czeisler et al., 1981.)
Awake
Asleep
185
Newborn
Stages of Sleep — The Nightly
Roller-Coaster
Gateway Question: Why do we sleep?
What causes sleep? Early sleep experts thought that something in
the bloodstream must cause sleep. But conjoined twins, whose
bodies are joined at birth, show that this is false ( Figure 6.4).
During waking hours, a sleep hormone (sleep-promoting chemical) collects in the brain and spinal cord, not in the blood. If this
substance is extracted from one animal and injected into another,
the second animal will sleep deeply for many hours (Cravatt et al.,
1995). Notice, however, that this explanation is incomplete. For
example, why would a well-rested person have to fight to stay
awake during a boring midday meeting?
Whether you are awake or asleep right now depends on the
balance between separate sleep and waking systems. Brain circuits
and chemicals in one of the systems promote sleep (Steiger, 2007).
A network of brain cells in the other system responds to chemicals
that inhibit sleep. The two systems seesaw back and forth, switching the brain between sleep and wakefulness (Lavie, 2001). Note
that the brain does not “shut down” during sleep. Rather, the pattern of activity changes.
•
1 year
4 years
10 years
•
6 PM
12
6 AM
12
Yale Joel/TimePix/Getty Images
Adult
6 PM
Figure 6.3
Development of sleep patterns. Short cycles of sleep and waking
gradually become the night-day cycle of an adult. Although most adults don’t take
naps, midafternoon sleepiness is a natural part of the sleep cycle. (Reprinted from
Electroencephalography & Clinical Neurophysiology, 17, Williams, Agnew, & Webb et al., Sleep
Patterns in young adults: An EEG study, 376-381, 1964, with permission from Elsevier.)
maintain alertness in people like truck drivers and hospital interns,
who often must fight to stay alert (Garbarino et al., 2004).
Busy people may be tempted to sleep less. However, people on
shortened cycles — for example, 3 hours of sleep to 6 hours
awake — often can’t get to sleep when the cycle calls for it. That’s
why astronauts continue to sleep on their normal earth schedule
while in space. Adapting to longer-than-normal days is more promising. Such days can be tailored to match natural sleep patterns,
which have a ratio of 2 to 1 between time awake and time asleep
Figure 6.4 These conjoined twins share the same blood supply, yet one
•sleeps
while the other is awake.
(Photo by Yale Joel, Life Magazine. © 1954 Time, Inc.)
Sleep-deprivation psychosis A major disruption of mental and
emotional functioning brought about by sleep loss.
Sleep patterns The order and timing of daily sleep and waking periods.
Sleep hormone A sleep-promoting substance found in the brain and
spinal cord.
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CHAPTER 6
(HIP-nik: sleep) jerk. (This is quite normal, so have no fear about
admitting to your friends that you fell asleep with a hypnic jerk.)
In stage 1 sleep the EEG is made up mainly of small, irregular
waves with some alpha. Persons awakened at this time may or may
not say they were asleep.
Sleep Stages
How does brain activity change when you fall asleep? Changes in
tiny electrical signals (brainwaves) generated by the brain can
be amplified and recorded with an electroencephalograph
(eh-LEK-tro-en-SEF-uh-lo-graf ), or EEG. When you are awake
and alert, the EEG reveals a pattern of small fast waves called
beta waves ( Figure 6.5). Immediately before sleep, the pattern
shifts to larger and slower waves called alpha waves. (Alpha
waves also occur when you are relaxed and allow your thoughts
to drift.) As the eyes close, breathing becomes slow and regular,
the pulse rate slows, and body temperature drops. Soon after, we
descend into slow-wave sleep through four distinct sleep stages.
Stage 2
•
As sleep deepens, body temperature drops further. Also, the EEG
begins to include sleep spindles, which are short bursts of distinctive brain-wave activity (Fogel et al., 2007). Spindles seem to mark
the true boundary of sleep. Within 4 minutes after spindles
appear, most people will say they were asleep.
Stage 3
Stage 1
In stage 3, a new brainwave called delta begins to appear. Delta
waves are very large and slow. They signal a move to deeper slowwave sleep and a further loss of consciousness.
As you enter light sleep (stage 1 sleep), your heart rate slows even
more. Breathing becomes more irregular. The muscles of your
body relax. This may trigger a reflex muscle twitch called a hypnic
Stage 4
Most people reach deep sleep (the deepest level of normal sleep)
in about 1 hour. Stage 4 brainwaves are almost pure slow-wave
delta, and the sleeper is in a state of oblivion. If you make a loud
noise during stage 4, the sleeper will wake up in a state of confusion and may not remember the noise.
BSIP/Photo Researchers, Inc.
The Dual Process Hypothesis of Sleep
(a)
•
Awake
Beta waves
Eyes closed,
relaxed
Alpha waves
Stage 1
Small, irregular
waves
Stage 2
Sleep spindles
Stage 3
Delta waves
appear
Stage 4
Mostly delta
(b)
Figure 6.5
(a) Photograph of an EEG recording session. The boy in the background is asleep. (b) Changes in brain-wave patterns associated with various stages
of sleep. Actually, most wave types are present at all times, but they occur more or
less frequently in various sleep stages.
There is much more to a night’s sleep than a simple descent into stage
4. Fluctuations in other sleep hormones cause recurring cycles of
deeper and lighter sleep throughout the night (Steiger, 2007). During these repeated periods of lighter sleep, a curious thing happens:
the sleeper’s eyes occasionally move under the eyelids. (If you ever get
a chance to watch a sleeping child, roommate, or spouse, you may see
these eye movements.) Rapid eye movements, or REMs, are associated with dreaming ( Figure 6.6). In addition to rapid eye movements, REM sleep is marked by a return of fast, irregular EEG patterns similar to stage 1 sleep. In fact, the brain is so active during
REM sleep that it looks as if the person is awake (Rock, 2004).
The two most basic states of sleep, then, are non-REM (NREM)
sleep (which occurs during stages 1, 2, 3, and 4) and REM sleep, with
its associated dreaming (Rock, 2004). Earlier, we noted some of the
biological benefits of sleep. According to the dual process hypothesis of
sleep, REM and NREM sleep have two added purposes: They help
“refresh” the brain and store memories (Ficca & Salzarulob, 2004).
•
The Function of NREM Sleep
What is the function of NREM sleep? NREM sleep is dream-free
about 90 percent of the time and is deepest early in the night during the first few stage 4 periods. Your first period of stage 1 sleep
usually lacks REMs and dreams. Later stage 1 periods typically
include a shift into REM sleep. Dreamless slow-wave NREM sleep
increases after physical exertion and may help us recover from
bodily fatigue. It also appears to “calm” the brain during the earlier
part of a night’s sleep (Tononi & Cirelli, 2003).
According to the dual process hypothesis, we are bombarded by
information throughout the day, which causes our neural net-
States of Consciousness
187
Hours of Sleep
24 Hours
1
2
3
4
5
6
7
8
Awake
NREM
Sleep stages
REM
Awake
REM
1
NREM 2
NREM 3
NREM 4
(a)
•
Dreams
(b)
Figure 6.6
(a) Average proportion of time adults spend daily in REM sleep and NREM sleep. REM periods add up to about 20 percent of total sleep
time. (b) Typical changes in stages of sleep during the night. Notice that dreams mostly coincide with REM periods.
works to become more and more active. As a result, your brain
requires more and more energy to continue functioning. Slow
wave sleep early in the night brings overall brain activation levels
back down, allowing a “fresh” approach to the next day.
Consider for a moment the amazing jumble of events that make
up a day. Some experiences are worth remembering (like what you
are reading right now, of course) and others are not so important
(like what you were thinking when you put on your socks). As
slow wave sleep reduces overall activation in the brain, less important experiences may fade away and be forgotten. If you wake up
feeling clearer about what you studied the previous night, it might
be because your brain doesn’t “sweat the small stuff ”!
The Function of REM Sleep
What then, is the purpose of REM sleep? According to the dual process
hypothesis, while NREM sleep “calms” the brain, REM sleep appears
to “sharpen” our memories of the previous day’s more important
experiences (Saxvig et al., 2008). Daytime stress tends to increase
REM sleep, which may rise dramatically when there is a death in the
family, trouble at work, a marital conflict, or other emotionally
charged events. The value of more REM sleep is that it helps us sort
and retain memories, especially memories about strategies for solving
problems (Walker & Stickgold, 2006). This is why, after studying for
a long period, you may remember more if you go to sleep, rather than
pulling an all-nighter. (REMember to get some REM!)
Early in life, REM sleep may stimulate the developing brain.
Newborn babies have lots of new experiences to process so they
spend a hearty 8 or 9 hours a day in REM sleep. That’s about 50
percent of their total sleep time.
REM Sleep and Dreaming
Roughly 85 percent of the time, people awakened during REMs
report vivid dreams. Some eye movements correspond to dream
activities. Dream that you are watching a tennis match, and you will
probably move your eyes from side to side. However, people who
were born blind still have REMs, so eye movements are not just a
result of “watching” dream images (Shafton, 1995). REM sleep is
easy to observe in pets, such as dogs and cats. Watch for eye and
face movements and irregular breathing. (You can forget about
your pet iguana, though. Reptiles show no signs of REM sleep.)
Dreams during REM sleep tend to be longer, clearer, more
detailed, more bizarre, and more “dream-like” than thoughts and
images that occur in NREM sleep (Hobson, Pace-Schott, & Stickgold, 2000). Also, brain areas associated with imagery and emotion become more active during REM sleep. This may explain why
REM dreams tend to be more vivid than NREM dreams (Braun,
Balkin, & Herscovitch, 1998; Rock, 2004).
Speaking very loosely, it’s as if the dreaming brain were reviewing messages left on a telephone answering machine, to decide
which are worth keeping. During the day, when information is
streaming in, the brain may be too busy to efficiently select useful
memories. When the conscious brain is “off-line,” we are better
able to build new memories.
What happens to the body when a person dreams? REM sleep is
a time of high emotion. The heart beats irregularly. Blood pressure
and breathing waver. Both males and females appear to be sexually
aroused: Men usually have an erection, and genital blood flow
increases in women. This occurs for all REM sleep, so it is not
strictly related to erotic dreams ( Jouvet, 1999).
Electroencephalograph (EEG) A device designed to detect, amplify,
and record electrical activity in the brain.
Beta waves Small, fast brain waves associated with being awake and alert.
Alpha waves Large, slow brain waves associated with relaxation
and falling asleep.
Sleep stages Levels of sleep identified by brain-wave patterns and
behavioral changes.
Light sleep Stage 1 sleep, marked by small irregular brainwaves and
some alpha waves.
Sleep spindles Distinctive bursts of brainwave activity that indicate a
person is asleep.
Delta waves Large, slow brainwaves that occur in deeper sleep (stages 3
and 4).
Deep sleep Stage 4 slow-wave sleep; the deepest form of normal sleep.
Rapid eye movements (REMs) Swift eye movements during sleep.
REM sleep Sleep marked by rapid eye movements and a return to stage
1 EEG patterns.
Non-REM (NREM) sleep Non–rapid eye movement sleep characteristic
of stages 2, 3, and 4.
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CHAPTER 6
C R IT ICAL T H I N KI N G
They Came from Outer Space?
During REM sleep, your body becomes quite still, as if you were
paralyzed. Imagine for a moment the results of acting out some of
your recent dreams. Very likely, REM-sleep paralysis prevents some
hilarious — and dangerous — nighttime escapades. When it fails,
some people thrash violently, leap out of bed, and may attack their
bed partners. A lack of muscle paralysis during REM sleep is called
REM behavior disorder (Ochoa & Pulido, 2005). One patient suffering from the disorder tied himself to his bed every night. That
way, he couldn’t jump up and crash into furniture or walls (Shafton,
1995). And yet sometimes sleep paralysis can go a little too far. (See
“They Came from Outer Space?”)
In a moment we will survey some additional sleep problems — if
you are still awake. First, here are a few questions to check your
memory of our discussion so far.
K NOW LEDGE B U I L D E R
Altered States and Sleep
RECITE
1. Changes in the quality and pattern of mental activity define
a. an EEG
b. an REM
c. SIDS
d. an ASC
2. Delusions and hallucinations typically continue for several days after
a sleep-deprived individual returns to normal sleep. T or F?
3. Alyssa experiences a microsleep while driving. Most likely, this indicates that she
a. was producing mostly beta waves
b. had high levels of sleep hormones in her bloodstream
c. switched from delta waves to alpha waves
d. was sleep deprived
some people who have sleep-related hallucinations believe they have been abducted
by space aliens or sexually abused (McNally
& Clancy, 2005).
Detroit Institute of the Arts/SuperStock
hypnopompic (hip-neh-POM-pik: “upon
awakening”) hallucinations. According to
psychologist Al Cheyne, these hallucinations may include bizarre experiences, such
as sensing that an alien being is in your
bedroom; feeling something pressing on
your chest, suffocating you; or feeling like
you are floating out of your body (Cheyne,
2005; Cheyne, Rueffer, & Newby-Clark,
1999).
Although most of us shrug off these weird
experiences, some people try to make sense
of them. Earlier in history, people interpreted
these hallucinated intruders as angels,
demons, or witches and believed that their
out-of-body experiences were real (Cheyne,
Rueffer, & Newby-Clark, 1999). However, as
our culture changes so do our interpretations
of sleep experiences. Today, for example,
Swiss artist Henry Fuseli drew on hypnopompic
imagery as an inspiration for his famous painting,
The Nightmare.
4. Older adults, and particularly the elderly, sleep more than children
do because the elderly are more easily fatigued. T or F?
5. Alpha waves are to presleep drowsiness as _____________________
___________ are to stage 4 sleep.
6. Rapid eye movements indicate that a person is in deep sleep. T or F?
7. Which of the following would normally be most incompatible with
moving your arms and legs while asleep?
a. REM sleep
b. sleep spindles
c. delta waves
d. NREM sleep
REFLECT
Critical Thinking
8. Why might it be better for the unscheduled human sleep–waking
cycle to average more than 24 hours, instead of less?
9. In addition to helping store memories, what biological advantages
might sleeping provide?
Relate
Make a quick list of some altered states of consciousness you have experienced. What do they have in common? How are they different? What
conditions caused them?
Imagine that you are a counselor at a sleep clinic. You must explain
the basics of sleep and dreaming to a new client who knows little about
these topics. Can you do it?
Answers: 1. d 2. F 3. d 4. F 5. delta waves 6. F 7. a 8. Sleep experts theorize that the 25-hour average leaves a little “slack” in the cycle. External
time markers can then retard the body cycle slightly to synchronize it
with light-dark cycles. If the body cycle were shorter than 24 hours, we
all might have to “stretch” every day to adjust. 9. Lowering body activity
and metabolism during sleep may help conserve energy and lengthen
life. Also, natural selection may have favored sleep because animals that
remained active at night probably had a higher chance of being killed.
(We’ll bet they had more fun, though.)
Imagine opening your eyes shortly before
dawn, attempting to roll over in your bed,
and suddenly realizing that you are entirely
paralyzed. While lying helplessly on your
back and unable to cry out for help, you
become aware of sinister figures lurking
in your bedroom. As they move closer to
your bed, your heart begins to pound violently and you feel as if you are suffocating.
You hear buzzing sounds and feel electrical
sensations shooting throughout your body.
Within moments, the visions vanish and you
can move once again. Terrified, you wonder
what has just happened (McNally & Clancy,
2005, p.114).
Sleep paralysis, which normally prevents
us from moving during REM sleep, can also
occur just as you begin to wake up. During
such episodes, people sometimes have
States of Consciousness
Gateway Question: What are some sleep disorders and unusual sleep
events?
Sleep quality has taken a beating in North America. Artificial
lighting, frenetic schedules, exciting pastimes, smoking, drinking,
overstimulation, and many other factors have contributed to a
near epidemic of sleep problems. Sleep disturbances are a serious
risk to health and happiness. Sleep clinics treat thousands of people each year who suffer from sleep disorders or complaints. These
disturbances range from daytime sleep attacks to sleepwalking and
terrifying nightmares ( Table 6.1). Let’s explore some of the more
interesting problems these people face.
•
Insomnia
Staring at the ceiling at 2 am is pretty low on most people’s list of
favorite pastimes. Yet about 60 million Americans have frequent
or chronic insomnia (NINDS, 2007). Insomnia includes diffi-
•
Table 6.1 Sleep Disturbances —
Things That Go Wrong in the Night
Hypersomnia
Excessive daytime sleepiness. This can result from
depression, insomnia, narcolepsy, sleep apnea,
sleep drunkenness, periodic limb movements,
drug abuse, and other problems.
Insomnia
Difficulty in getting to sleep or staying asleep; also,
not feeling rested after sleeping.
Narcolepsy
Sudden, irresistible, daytime sleep attacks that may
last anywhere from a few minutes to a half hour.
Victims may fall asleep while standing, talking, or
even driving.
Nightmare
disorder
Vivid, recurrent nightmares that significantly disturb
sleep.
Periodic limb
movement
syndrome
Muscle twitches (primarily affecting the legs) that
occur every 20 to 40 seconds and severely disturb
sleep.
REM behavior
disorder
A failure of normal muscle paralysis, leading to violent actions during REM sleep.
Restless legs
syndrome
An irresistible urge to move the legs to relieve sensations of creeping, tingling, prickling, aching, or
tension.
Sleep apnea
During sleep, breathing stops for 20 seconds or
more until the person wakes a little, gulps in
air, and settles back to sleep; this cycle may be
repeated hundreds of times per night.
Sleep
drunkenness
A slow transition to clear consciousness after awakening; sometimes associated with irritable or
aggressive behavior.
Sleep terror
disorder
The repeated occurrence of night terrors that significantly disturb sleep.
Sleep-wake
schedule
disorder
A mismatch between the sleep-wake schedule
demanded by a person’s bodily rhythm and that
demanded by the environment.
Sleepwalking
disorder
Repeated incidents of leaving bed and walking
about while asleep.
culty in going to sleep, frequent nighttime awakenings, waking too
early, or a combination of these problems. Insomnia can harm
people’s work, health, and relationships (Sateia & Nowell, 2004).
Types and Causes of Insomnia
Worry, stress, and excitement can cause temporary insomnia and a
self-defeating cycle. First, excess mental activity (“I can’t stop turning things over in my mind”) and heightened arousal block sleep.
Then, frustration and anger over not being able to sleep cause
more worry and arousal. This further delays sleep, which causes
more frustration, and so on (Espie, 2002). A good way to beat this
cycle is to avoid fighting it. Get up and do something useful or
satisfying when you can’t sleep. (Reading a textbook might be a
good choice of useful activities.) Return to bed only when you
begin to feel that you are struggling to stay awake. If sleeping problems last for more than 3 weeks, then a diagnosis of chronic insomnia can be made.
Drug-dependency insomnia (sleep loss caused by withdrawal
from sleeping pills) can also occur. There is real irony in the billion
dollars a year North Americans spend on sleeping pills. Nonprescription sleeping pills such as Sominex, Nytol, and Sleep-Eze have
little sleep-inducing effect. Barbiturates are even worse. These prescription sedatives decrease both stage 4 sleep and REM sleep,
drastically lowering sleep quality. In addition, many users become
“sleeping-pill junkies” who need an ever-greater number of pills to
get to sleep. Victims must be painstakingly weaned from their sleep
medicines. Otherwise, terrible nightmares and “rebound insomnia”
may drive them back to drug use. It’s worth remembering that
although alcohol and other depressant drugs may help a person get
to sleep, they greatly reduce sleep quality (Nau & Lichstein, 2005).
Even newer drugs, such as Ambien and Lunesta, which induce
The New Yorker Collection 2006 Barbara Smaller from The Cartoon Bank. All
Rights Reserved.
Sleep Disturbances — Showing
Nightly: Sleep Wars!
Insomnia Difficulty in getting to sleep or staying asleep.
Bond & Wooten, 1996; DSM-IV-TR, 2000; Hauri & Linde, 1990
189
190
CHAPTER 6
sleep, have drawbacks. Possible side effects include amnesia,
impaired judgment, increased appetite, decreased sex drive, depression, and sleepwalking. Rebound insomnia is also a risk, making
these drugs at best a temporary remedy for insomnia.
Behavioral Remedies for Insomnia
If sleeping pills are a poor way to treat insomnia, what can be done?
Sleep specialists prefer to treat insomnia with lifestyle changes and
behavioral techniques (Montgomery & Dennis, 2004). Treatment
for chronic insomnia usually begins with a careful analysis of a
patient’s sleep habits, lifestyle, stress levels, and medical problems.
All the approaches discussed in the following list are helpful for
treating insomnia (Nau & Lichstein, 2005):
1. Stimulus control. Insisting on a regular schedule helps
establish a firm body rhythm, greatly improving sleep. This
is best achieved by exercising stimulus control, which refers
to linking a response with specific stimuli. It is important to
get up and go to sleep at the same time each day, including
weekends (Bootzin & Epstein, 2000). In addition, insomniacs
are told to avoid doing anything but sleeping when they are in
bed. They are not to study, eat, watch TV, read, pay the bills,
worry, or even think in bed. (Lovemaking is okay, however.)
In this way, only sleeping and relaxation become associated
with going to bed at specific times (Bootzin & Epstein, 2000).
2. Sleep restriction. Even if an entire night’s sleep is missed, it
is important not to sleep late in the morning, nap more than
an hour, sleep during the evening, or go to bed early the following night. Instead, restricting sleep to normal bedtime
hours avoids fragmenting sleep rhythms (Shneerson, 2005).
3. Paradoxical intention. Another helpful approach is to
remove the pressures of trying to go to sleep. Instead, the
goal becomes trying to keep the eyes open (in the dark) and
stay awake as long as possible (Nau & Lichstein, 2005). This
allows sleep to come unexpectedly and lowers performance
anxiety (Espie, 2002).
4. Relaxation. Some insomniacs lower their arousal before
sleep by using a physical or mental strategy for relaxing, such
as progressive muscle relaxation, meditation, or blotting out
worries with calming images. It is also helpful to schedule
time in the early evening to write down worries or concerns
and plan what to do about them the next day, in order to set
them aside before going to bed.
6. Food intake. What you eat can affect how easily you get
to sleep. Eating starchy foods increases the amount of tryptophan (TRIP-tuh-fan: an amino acid) reaching the brain.
More tryptophan, in turn, increases the amount of serotonin
in the brain, which is associated with relaxation, a positive
mood, and sleepiness. Thus, to promote sleep, try eating a
starchy snack, such as cookies, bread, pasta, oatmeal, pretzels,
or dry cereal. If you really want to drop the bomb on insomnia, try eating a baked potato (which may be the world’s largest sleeping pill!) (Sahelian, 1998).
7. Stimulants. Stimulants, such as coffee and cigarettes, should
be avoided. It is also worth remembering that alcohol,
although not a stimulant, impairs sleep quality.
Sleepwalking, Sleeptalking, and Sleepsex
Sleepsex? As strange as it may seem, many waking behaviors can be
engaged in while asleep, such as driving a car, cooking, playing a
musical instrument, and eating (Plazzi et al., 2005). The most
famous, sleepwalking, is eerie and fascinating in its own right.
Somnambulists (som-NAM-bue-lists: those who sleepwalk) avoid
obstacles, descend stairways, and on rare occasions may step out of
windows or in front of automobiles. Sleepwalkers have been
observed jumping into lakes, urinating in garbage pails or closets
(phew!), shuffling furniture around, and even brandishing weapons (Schenck & Mahowald, 2005).
The sleepwalker’s eyes are usually open, but a blank face and
shuffling feet reveal that the person is still asleep. If you find someone sleepwalking, you should gently guide the person back to bed.
Awakening a sleepwalker does no harm, but it is not necessary.
Does sleepwalking occur during dreaming? No. Remember that
people are normally immobilized during REM sleep. EEG studies
have shown that somnambulism occurs during NREM stages 3
and 4 (Stein & Ferber, 2001). Sleeptalking also occurs mostly during NREM sleep. The link with deep sleep explains why sleeptalking makes little sense and why sleepwalkers are confused and
remember little when awakened (DSM-IV-TR, 2000).
Oh, yes, you’re curious about sleepsex. There is, of course, an
official name for it: sexsomnia (Shapiro, Trajanovic, & Fedoroff,
2003). Sexsomnia is not as exciting as it might sound: Just imagine
being startled wide awake by your bed partner, who is asleep but
attempting to have sex with you (Mangan, 2004).
Nightmares and Night Terrors
bridges
Learning how to achieve deep relaxation is a highly useful
skill. See Chapter 15, pages 505–507, for more information.
5. Exercise. Strenuous exercise during the day promotes sleep.
It is best if done about 6 hours before bedtime (Maas, 1999).
However, exercise in the evening is helpful only if it is very
light.
Stage 4 sleep is also the realm of night terrors. These frightening
episodes are quite different from ordinary nightmares ( Table 6.2).
A nightmare is simply a bad dream that takes place during REM
sleep. Frequently occurring nightmares (one a week or more) are
associated with higher levels of psychological distress (Levin & Fireman, 2002). During stage 4 night terrors, a person suffers total
panic and may hallucinate frightening dream images into the bedroom. An attack may last 15 or 20 minutes. When it is over, the
person awakens drenched in sweat but only vaguely remembers
the terror. Because night terrors occur during NREM sleep (when
•
191
States of Consciousness
Table 6.2
• Was It a Nightmare or a Night Terror?
Nightmare
Night Terror
Stage of sleep
REM
NREM
Activity
Slight or no
movement
Violent body movement, sits up, cries
out, may run
Emotion
Fear or anxiety
Terror and disorganizing panic
Mental state when
awakened
Coherent, can be
calmed
Incoherent, disoriented,
cannot be calmed,
may be hallucinating
Physiological
changes
No perspiration
Perspires heavily
Recall
Dream activity usually remembered
Amnesia for episode
the body is not immobilized), victims may sit up, scream, get out of
bed, or run around the room. Victims remember little afterward.
(Other family members, however, may have a story to tell.) Night
terrors are most common in childhood, but they continue to plague
about 2 out of every 100 adults (Kataria, 2004; Ohayon, Guilleminault, & Priest, 1999).
most effective treatments is the use of a continuous positive airway
pressure (CPAP) mask to aid breathing during sleep. Other treatments include weight loss and surgery for breathing obstructions
(Collop, 2005).
SIDS
Sleep apnea is suspected as one cause of sudden infant death syndrome (SIDS), or “crib death.” Each year 2500 babies are victims
of SIDS (NICHD, 2006). In the “typical” crib death, a slightly
premature or small baby with some signs of a cold or cough is
bundled up and put to bed. A short time later, parents find the
child has died. A baby deprived of air will normally struggle to
begin breathing again. However, SIDS babies seem to have a weak
arousal reflex. This prevents them from changing positions and
resuming breathing after an episode of apnea (Horne et al., 2001).
Babies at risk for SIDS must be carefully watched for the first
6 months of life. To aid parents in this task, a special monitor may
be used that sounds an alarm when breathing or pulse becomes
weak ( Figure 6.7). Babies at risk for SIDS are often premature;
have a shrill, high-pitched cry; engage in “snoring,” breath-holding, or frequent awakening at night; breathe mainly through an
open mouth; or remain passive when their face rolls into a pillow
or blanket.
•
How to Eliminate a Nightmare
Sleep Apnea
Some sage once said, “Laugh and the whole world laughs with
you; snore and you sleep alone.” Nightly “wood sawing” is often
harmless, but it can signal a serious problem. A person who snores
loudly, with short silences and loud gasps or snorts, may suffer
from apnea (AP-nee-ah: interrupted breathing). In sleep apnea,
breathing stops for periods of 20 seconds to 2 minutes. As the
need for oxygen becomes intense, the person wakes a little and
gulps in air. She or he then settles back to sleep. But soon, breathing stops again. This cycle is repeated hundreds of times a night.
As you might guess, apnea victims are extremely sleepy during the
day (Collop, 2005).
What causes sleep apnea? Some cases occur because the brain
stops sending signals to the diaphragm to maintain breathing.
Another cause is blockage of the upper air passages. One of the
Michael Newman/PhotoEdit
Is there any way to stop a recurring nightmare? A bad nightmare can
be worse than any horror movie. It’s easy to leave a theater, but we
often remain trapped in terrifying dreams. Nevertheless, most
nightmares can be banished by following three simple steps. First,
write down your nightmare, describing it in detail. Next, change
the dream any way you wish, being sure to spell out the details of
the new dream. The third step is imagery rehearsal, in which you
mentally rehearse the changed dream before you fall asleep again
(Krakow & Zadra, 2006). Imagery rehearsal may work because it
makes upsetting dreams familiar while a person is awake and feeling safe. Or perhaps it mentally “reprograms” future dream content. In any case, the technique has helped many people.
Figure 6.7 Infants at risk for SIDS are often attached to devices that monitor
•breathing
and heart rate during sleep. An alarm sounds to alert parents if either
pulse or respiration falters. SIDS rarely occurs after an infant is 1 year old. Babies at
risk for SIDS should be placed on their sides or on their backs.
Stimulus control Linking a particular response with specific stimuli.
Somnambulists People who sleepwalk; occurs during NREM sleep.
Nightmare A bad dream that occurs during REM sleep.
Night terror A state of panic during NREM sleep.
Sleep apnea Repeated interruption of breathing during sleep.
Sudden infant death syndrome (SIDS) The sudden, unexplained
death of an apparently healthy infant.
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CHAPTER 6
“Back to Sleep”
Sleeping position is another major risk factor for SIDS. Healthy
infants are better off sleeping on their backs or sides. (Premature
babies, those with respiratory problems, and those who often
vomit may need to sleep facedown. Ask a pediatrician for guidance.) Remember, “back to sleep” is the safest position for most
infants (Hauck et al., 2002). It is also worth eliminating soft
objects such as pillows, quilts, comforters, or sheepskins from the
baby’s bed.
Narcolepsy
One of the most dramatic sleep problems is narcolepsy (NARkoe-lep-see), or sudden, irresistible sleep attacks. These last anywhere from a few minutes to a half hour. Victims may fall asleep
while standing, talking, or even driving. Emotional excitement,
especially laughter, commonly triggers narcolepsy. (Tell an especially good joke and a narcoleptic may fall asleep.) More than half
of all victims also suffer from cataplexy (CAT-uh-plex-see), a sudden temporary paralysis of the muscles, leading to complete body
collapse. It’s easy to understand why narcolepsy can devastate
careers and relationships (Thorpy, 2006).
Because sudden paralysis happens during dreaming, is there a connection between narcolepsy and REM sleep? Yes, narcoleptics tend
to fall directly into REM sleep. Thus, the narcoleptic’s sleep
attacks and paralysis appear to occur when REM sleep intrudes
into the waking state (Mignot, 2001).
Fortunately, narcolepsy is rare. It runs in families, which suggests that it is hereditary (Chabas et al., 2003). In fact, this has
been confirmed by breeding several generations of narcoleptic
dogs. (These dogs, by the way, are simply outstanding at learning
the trick “Roll over and play dead.”) There is no known cure for
narcolepsy, but a drug named sodium oxybate reduces the frequency and intensity of attacks (Thorpy, 2006).
Dreams — A Separate Reality?
Gateway Question: Do dreams have meaning?
When REM sleep was discovered in 1952, it ushered in a “Golden
Era” of dream inquiry. To conclude our discussion of sleep, let’s
consider some age-old questions about dreaming.
Does everyone dream? Do dreams occur in an instant? Most
people dream four or five times a night, but not all people remember their dreams. “Nondreamers” are often surprised by their
dreams when first awakened during REM sleep. Dreams are usually spaced about 90 minutes apart. The first dream lasts only
about 10 minutes; the last averages 30 minutes and may run as
long as 50. Dreams, therefore, occur in real time, not as a “flash”
(Shafton, 1995).
REM Sleep Revisited
How important is REM sleep? To answer this question, sleep expert
William Dement awakened volunteers each time they entered
REM sleep. Soon, their need for “dream time” grew more urgent.
By the fifth night, many had to be awakened 20 or 30 times to
prevent REM sleep. When the volunteers were finally allowed to
sleep undisturbed, they dreamed extra amounts. This effect, called
a REM rebound, explains why alcoholics have horrible nightmares after they quit drinking. Alcohol reduces sleep quality by
suppressing REM sleep, thus setting up a powerful rebound when
it is withdrawn (Stein & Friedmann, 2005).
Dement’s volunteers complained of memory lapses, poor concentration, and anxiety. For a while, it was thought that people deprived
of REM sleep might go crazy. But later experiments showed that
missing any sleep stage can cause a rebound for that stage. In general,
daytime disturbances are related to the total amount of sleep lost, not
to the type of sleep lost (Devoto et al., 1999).
Dream Theories
How meaningful are dreams? Some theorists believe that dreams
have deeply hidden meanings. Others regard dreams as nearly
meaningless. Yet others hold that dreams reflect our waking
thoughts, fantasies, and emotions (Beck, 2004). Let’s examine all
three views.
Psychodynamic Dream Theory
Psychodynamic theories of dreaming emphasize internal conflicts and unconscious forces. Sigmund Freud’s landmark book,
The Interpretation of Dreams (1900), first advanced the idea that
many dreams are based on wish fulfillment (an expression of
unconscious desires). One of Freud’s key proposals was that dreams
express unconscious desires and conflicts as disguised dream symbols (images that have deeper symbolic meaning). Understanding
a dream, then, requires analyzing the dream’s manifest content
(obvious, visible meaning) to uncover its latent content (hidden,
symbolic meaning).
For instance, a woman who dreams of stealing her best friend’s
wedding ring and placing it on her own hand may be unwilling to
consciously admit that she is sexually attracted to her best friend’s
husband. Similarly, a journey might symbolize death, and horseback riding or dancing, sexual intercourse.
bridges
Interpreting dreams is an important part of Freudian
psychoanalysis. See Chapter 15, pages 498–500.
Do all dreams have hidden meanings? Probably not. Freud realized that some dreams are trivial “day residues” or carryovers from
ordinary waking events. On the other hand, dreams do tend to
reflect a person’s current concerns, so Freud wasn’t entirely wrong.
The Activation-Synthesis Hypothesis
Psychiatrists Allan Hobson and Robert McCarley have a radically
different view of dreaming, called the activation-synthesis
hypothesis. They believe that during REM sleep several lower
brain centers are “turned on” (activated) in more or less random
States of Consciousness
193
SuperStock, Inc./SuperStock
Dream Worlds
According to psychodynamic theory, dream imagery often has symbolic meaning. How would you interpret French artist Henri Rousseau’s dreamlike image,
titled The Dream? The fact that dreams don’t have a single unambiguous meaning is one of the shortcomings of Freudian dream theory.
fashion. However, messages from the cells are blocked from reaching the body, so no movement occurs. Nevertheless, the cells continue to tell higher brain areas of their activities. Struggling to
interpret this random information, the brain searches through
stored memories and manufactures (synthesizes) a dream (Hobson,
2000; 2005). However, frontal areas of the cortex, which control
higher mental abilities, are mostly shut down during REM sleep.
This explains why dreams are more primitive and more bizarre
than daytime thoughts (Hobson, 2000).
How does that help explain dream content? According to the
activation-synthesis hypothesis, dreams are basically meaningless.
Let’s use the classic chase dream as an example. In such dreams we
feel we are running but not going anywhere. This occurs because
the brain is told the body is running, but it gets no feedback from
the motionless legs. To try to make sense of this information, the
brain creates a chase drama. A similar process probably explains
dreams of floating or flying.
So dreams have no meaning? The activation-synthesis hypothesis doesn’t rule out the idea that dreams have some meaning.
Because dreams are created from memories and past experiences,
parts of dreams can sometimes reflect each person’s mental life,
emotions, and concerns (Hobson, 2000).
Neurocognitive Dream Theory
William Domhoff offers a third view of dreaming. According to
his neurocognitive dream theory, dreams actually have much in
common with waking thoughts and emotions. Most dreams reflect
ordinary waking concerns. Domhoff believes this is true because
many brain areas that are active when we are awake remain active
during dreaming (Domhoff, 2001; 2003; 2005). From this perspective, our dreams are a conscious expression of REM sleep
processes that are sorting and storing daily experiences. Thus, we
shouldn’t be surprised if a student who is angry at a teacher dreams
of embarrassing the teacher in class, a lonely person dreams of
romance, or a hungry child dreams of food. It is not necessary to
seek deep symbolic meanings to understand these dreams.
Which dream theory is the most widely accepted? Each theory has
strengths and weaknesses. However, studies of dream content
do support neurocognitive theory’s focus on the continuity
between dreams and waking thought. Rather than being exotic
or bizarre, most dreams reflect everyday events (Hall, 1966;
Pesant & Zadra, 2006). For example, athletes tend to dream
about the previous day’s athletic activities (Erlacher & Schredl,
2004). In general, the favorite dream setting is a familiar room
in a house. Action usually takes place between the dreamer and
two or three other emotionally important people — friends,
enemies, loved ones, or employers. Dream actions are also
mostly familiar: running, jumping, riding, sitting, talking, and
watching. About half of all dreams have sexual elements. Dreams
of flying, floating, and falling occur less frequently. However,
note that such dreams lend some support to the activationsynthesis hypothesis, because they are not everyday events.
(Unless you are a trapeze artist.)
Are most dreams happy or sad? If you ask people in the morning
what they dreamed about, they mention more unpleasant emotions than pleasant emotions (Merritt et al., 1994). However, it
may be that dreams of fear, anger, or sadness are easier to remember. When people are awakened during REM sleep, they report
equal numbers of positive and negative emotions (Fosse, Stickgold, & Hobson, 2001).
Even if many dreams can be viewed as just a different form of
thought, many psychologists continue to believe that some
dreams have deeper meaning (White & Taytroe, 2003; Wilkinson, 2006). There seems to be little doubt that dreams can make
a difference in our lives: Veteran sleep researcher William
Dement once dreamed that he had lung cancer. In the dream a
doctor told Dement he would die soon. At the time, Dement
was smoking two packs of cigarettes a day. He says, “I will never
Narcolepsy A sudden, irresistible sleep attack.
Cataplexy A sudden temporary paralysis of the muscles.
REM rebound The occurrence of extra rapid eye movement sleep
following REM sleep deprivation.
Psychodynamic theory Any theory of behavior that emphasizes
internal conflicts, motives, and unconscious forces.
Wish fulfillment Freudian belief that many dreams express
unconscious desires.
Dream symbols Images in dreams that serve as visible signs of hidden
ideas, desires, impulses, emotions, relationships, and so forth.
Manifest dream content The surface, “visible” content of a dream;
dream images as they are remembered by the dreamer.
Latent dream content The hidden or symbolic meaning of a dream, as
revealed by dream interpretation and analysis.
Activation-synthesis hypothesis An attempt to explain how random
activity in lower brain centers results in the manufacture of relatively
bizarre dreams by higher brain centers.
Neurocognitive dream theory Proposal that dreams reflect everyday
waking thoughts and emotions.
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CHAPTER 6
forget the surprise, joy, and exquisite relief of waking up. I felt
reborn.” Dement quit smoking the following day. (For more
information about dreaming, see the Psychology in Action section later in this chapter.)
K NOW LEDGE B U I L D E R
Sleep Disturbances and Dreaming
RECITE
1. Which of the following is not a behavioral remedy for insomnia?
a. daily hypersomnia
b. stimulus control
c. progressive relaxation
d. paradoxical intention
2. Eating a snack that is nearly all starch can promote sleep because it
increases __________ in the brain.
a. beta waves
b. tryptophan
c. EEG activity
d. hypnic cycling
3. Night terrors, sleepwalking, and sleeptalking all occur during stage 1,
NREM sleep. T or F?
4. Sleep _________________ is suspected as one cause of SIDS.
5. People who suffer from sudden daytime sleep attacks have which
sleep disorder?
a. narcolepsy
b. REM behavior disorder
c. somnambulism
d. sleep spindling
6. According to the activation-synthesis hypothesis of dreaming,
dreams are constructed from __________________________ to
explain messages received from nerve cells controlling eye movement, balance, and bodily activity.
7. The favored setting for dreams is
a. work
b. school
c. outdoors or unfamiliar places
d. familiar rooms
8. Sharpening memories and facilitating their storage is one function of
a. activation-synthesis cycles
b. REM sleep
c. deep sleep
d. NREM sleep
REFLECT
Critical Thinking
9. Even without being told that somnambulism is an NREM event, you
could have predicted that sleepwalking doesn’t occur during dreaming. Why?
Relate
Almost everyone suffers from insomnia at least occasionally. Are any of
the techniques for combating insomnia similar to strategies you have
discovered on your own?
How many sleep disturbances can you name (including those listed
in Table 6.1)? Are there any that you have experienced? Which do you
think would be most disruptive?
Do you think the activation-synthesis hypothesis provides an adequate explanation of your own dreams? Have you had dreams that seem
to reflect Freudian wish fulfillment? Do you think your dreams have symbolic meaning or reflect everyday concerns?
•
Hypnosis — Look into My Eyes
Gateway Question: What is hypnosis?
“Your body is becoming heavy. You can barely keep your eyes
open. You are so tired you can’t move. Relax. Let go. Relax. Close
your eyes and relax.” These are the last words a textbook should
ever say to you, and the first a hypnotist might say.
Interest in hypnosis began in the 1700s with Austrian doctor
Franz Mesmer, whose name gave us the term mesmerize (to hypnotize). Mesmer believed he could cure disease with magnets. Mesmer’s strange “treatments” are related to hypnosis because they
actually relied on the power of suggestion, not magnetism (Waterfield, 2002). For a time, Mesmer enjoyed quite a following. In the
end, however, his theories of “animal magnetism” were rejected
and he was branded a fraud.
The term hypnosis was later coined by English surgeon James
Braid. The Greek word hypnos means “sleep,” and Braid used it
to describe the hypnotic state. Today we know that hypnosis is
not sleep. Confusion about this point remains because some
hypnotists give the suggestion, “Sleep, sleep.” However, EEG
patterns recorded during hypnosis are different from those
observed when a person is asleep or pretending to be hypnotized
(Barabasz, 2000).
Theories of Hypnosis
If hypnosis isn’t sleep, then what is it? That’s a good question. Hypnosis is often defined as an altered state of consciousness, characterized by narrowed attention and an increased openness to suggestion (Kallio & Revonsuo, 2003; Kosslyn et al., 2000). Notice
that this definition assumes hypnosis is a distinct state of consciousness.
The best-known state theory of hypnosis was proposed by
Ernest Hilgard (1904–2001), who argued that hypnosis causes a
dissociative state, or “split” in awareness. To illustrate, he asked
hypnotized subjects to plunge one hand into a painful bath of ice
water. Subjects told to feel no pain said they felt none. The same
subjects were then asked if there was any part of their mind that
did feel pain. With their free hand, many wrote, “It hurts,” or
“Stop it, you’re hurting me,” while they continued to act painfree (Hilgard, 1977, 1994). Thus, one part of the hypnotized
person says there is no pain and acts as if there is none. Another
part, which Hilgard calls the hidden observer, is aware of the pain
but remains in the background. The hidden observer is a
detached part of the hypnotized person’s awareness that silently
observes events.
In contrast, nonstate theorists argue that hypnosis is not a distinct state at all. Instead it is merely a blend of conformity, relaxation, imagination, obedience, and role-playing (Kirsch, 2005).
For example, many theorists believe that all hypnosis is really selfhypnosis (autosuggestion). From this perspective, a hypnotist
merely helps another person to follow a series of suggestions.
These suggestions, in turn, alter sensations, perceptions, thoughts,
feelings, and behaviors (Lynn & Kirsch, 2006). (See “Swinging
Suggestions.”)
Answers: 1. a 2. b 3. F 4. apnea 5. a 6. memories 7. d 8. b 9. Because people
are immobilized during REM sleep and REM sleep is strongly associated
with dreaming. This makes it unlikely that sleepwalkers are acting out
dreams.
195
States of Consciousness
D ISCOVERI N G P S Y CH OL O G Y
Here’s a demonstration you can use to gain
insight into hypnosis. Tie a short length of
string (about 6 inches) to a small, heavy
object, such as a ring or a small metal nut.
Hold the ring at eye level, about a foot from
your face. Concentrate on the ring and notice
that it will begin to move, ever so slightly. As
it does, focus all your attention on the ring.
Narrow your attention to a beam of energy
and mentally push the ring away from you.
Each time the ring swings away, push on it,
using only mental force. Then release it and
let it swing back toward you. Continue to
mentally push and release the ring until it is
swinging freely. For the best results, try this
now, before reading more.
Did the ring move? If it did, you used autosuggestion to influence your own behavior in
a subtle way. Suggestions that the ring would
swing caused your hand to make tiny micromuscular movements. These, in turn, caused
the ring to move — no special mental powers
or supernatural forces are involved.
As is true of hypnotic suggestion, the ring’s
movement probably seemed to be automatic. Obviously, you could just intentionally
swing the ring. However, if you responded to
suggestion, the movement seemed to happen without any effort on your part. In the
same way, when people are hypnotized, their
actions seem to occur without any voluntary
intent. Incidentally, autosuggestion likely
underlies other phenomena, such as how
Ouija boards answer questions without any
conscious movements by the person using
the pointer.
Dennis Coon
Swinging Suggestions
Regardless of which theoretical approach finally prevails, both
views suggest that hypnosis can be explained by normal principles.
It is not mysterious or “magical,” despite what stage hypnotists
might have you think.
remain in control of their behavior and aware of what is going on.
For instance, most people will not act out hypnotic suggestions
that they consider immoral or repulsive (such as disrobing in public or harming someone) (Kirsch & Lynn, 1995).
The Reality of Hypnosis
Hypnotic Susceptibility
How is hypnosis done? Hypnotists use many different methods.
Still, all techniques encourage a person (1) to focus attention on
what is being said, (2) to relax and feel tired, (3) to “let go” and
accept suggestions easily, and (4) to use vivid imagination (Druckman & Bjork, 1994). Basically, you must cooperate to become
hypnotized.
What does it feel like to be hypnotized? You might be surprised
at some of your actions during hypnosis. You also might have
mild feelings of floating, sinking, anesthesia, or separation from
your body. Personal experiences vary widely. A key element in
hypnosis is the basic suggestion effect (a tendency of hypnotized
persons to carry out suggested actions as if they were involuntary). Hypnotized persons feel like their actions and experiences
are automatic — they seem to happen without effort. Here is how
one person described his hypnotic session:
Can everyone be hypnotized? About 8 people out of 10 can be hypnotized, but only 4 out of 10 will be good hypnotic subjects. People who are imaginative and prone to fantasy are often highly
responsive to hypnosis (Kallio & Revonsuo, 2003). But people
who lack these traits may also be hypnotized. If you are willing to
be hypnotized, chances are good that you could be. Hypnosis
depends more on the efforts and abilities of the hypnotized person
than the skills of the hypnotist. But make no mistake; people who
are hypnotized are not merely faking their responses.
Hypnotic susceptibility refers to how easily a person can
become hypnotized. It is measured by giving a series of suggestions
and counting the number of times a person responds. A typical
hypnotic test is the Stanford Hypnotic Susceptibility Scale, shown
I felt lethargic, my eyes going out of focus and wanting to close. My hands
felt real light. . . . I felt I was sinking deeper into the chair. . . . I felt like I
wanted to relax more and more. . . . My responses were more automatic.
I didn’t have to wish to do things so much or want to do them. . . . I just did
them. . . . I felt floating . . . very close to sleep. (Hilgard, 1968)
Could I be hypnotized against my will? Contrary to the way
hypnosis is portrayed in movies, hypnotized people generally
Hypnosis An altered state of consciousness characterized by narrowed
attention and increased suggestibility.
Hidden observer A detached part of the hypnotized person’s
awareness that silently observes events.
Basic suggestion effect The tendency of hypnotized persons to carry
out suggested actions as if they were involuntary.
Hypnotic susceptibility One’s capacity for becoming hypnotized.
196
CHAPTER 6
Table 6.3
• Stanford Hypnotic Susceptibility Scale
Suggested Behavior
Effects of Hypnosis
What can (and cannot) be achieved with hypnosis? Many abilities
have been tested during hypnosis, leading to the following conclusions (Burgess & Kirsch, 1999; Chaves, 2000):
Criterion of Passing
1. Postural sway
Falls without forcing
2. Eye closure
Closes eyes without forcing
3. Hand lowering (left)
Lowers at least 6 inches by end of
10 seconds
4. Immobilization (right arm)
Arm rises less than 1 inch in 10
seconds
5. Finger lock
Incomplete separation of fingers
at end of 10 seconds
6. Arm rigidity (left arm)
Less than 2 inches of arm bending
in 10 seconds
7. Hands moving together
Hands at least as close as 6 inches
after 10 seconds
8. Verbal inhibition (name)
Name unspoken in 10 seconds
9. Hallucination (fly)
Any movement, grimacing,
acknowledgment of effect
1. Superhuman acts of strength. Hypnosis has no more effect
on physical strength than instructions that encourage a person to make his or her best effort.
2. Memory. There is some evidence that hypnosis can enhance
memory (Wagstaff et al., 2004). However, it frequently
increases the number of false memories as well. For this reason, many states now bar persons from testifying in court if
they were hypnotized to improve their memory of a crime
they witnessed.
bridges
10. Eye catalepsy
Eyes remain closed at end of 10
seconds
11. Posthypnotic (changes chairs)
Any partial movement response
12. Amnesia test
Three or fewer items recalled
Adapted from Weitzenhoffer & Hilgard, 1959.
•
in Table 6.3. In the test, various suggestions are made, and the
person’s response is noted. For instance, you might be told that
your left arm is becoming more and more rigid and that it will not
bend. If you can’t bend your arm during the next 10 seconds,
you have shown susceptibility to hypnotic suggestions. (Also see
Figure 6.8.)
•
Should the police use hypnosis to enhance the memories of
witnesses? The evidence generally says no. See Chapter 8,
page 258.
3. Amnesia. A person told not to remember something heard
during hypnosis may claim not to remember. In some
instances this may be nothing more than a deliberate attempt
to avoid thinking about specific ideas. However, brief memory loss of this type actually does seem to occur (Barnier,
McConkey, & Wright, 2004).
4. Pain relief. Hypnosis can relieve pain (Keefe, Abernethy, &
Campbell, 2005). It can be especially useful when chemical
painkillers are ineffective. For instance, hypnosis can reduce
phantom limb pain (Oakley, Whitman, & Halligan, 2002).
(As discussed in Chapter 4, amputees sometimes feel phantom pain that seems to come from a missing limb.)
5. Age regression. Given the proper suggestions, some hypnotized people appear to “regress” to childhood. However, most
theorists now believe that “age-regressed” subjects are only
acting out a suggested role.
6. Sensory changes. Hypnotic suggestions concerning sensations
are among the most effective. Given the proper instructions,
a person can be made to smell a small bottle of ammonia and
respond as if it were a wonderful perfume. It is also possible to
alter color vision, hearing sensitivity, time sense, perception of
illusions, and many other sensory responses.
Dennis Coon
Hypnosis is a valuable tool. It can help people relax, feel less
pain, and make better progress in therapy (Chapman, 2006). Generally, hypnosis is more successful at changing subjective experience
than it is at modifying behaviors such as smoking or overeating.
6.8 In one test of hypnotizability, subjects attempt to pull their hands
•apartFigure
after hearing suggestions that their fingers are “locked” together.
Stage Hypnosis
On stage the hypnotist intones, “When I count to three, you will
imagine that you are on a train to Disneyland and growing younger
and younger as the train approaches.” Responding to these sugges-
States of Consciousness
tions, grown men and women begin to giggle and squirm like
children on their way to a circus.
How do stage entertainers use hypnosis to get people to do strange
things? They don’t. Little or no hypnosis is needed to do a good
hypnosis act. Stage hypnosis is often merely a simulation of hypnotic effects. Stage hypnotists make use of several features of the
stage setting to perform their act (Barber, 2000).
1. Waking suggestibility. We are all more or less open to suggestion, but on stage people are unusually cooperative because
they don’t want to “spoil the act.” As a result, they will readily
follow almost any instruction given by the entertainer.
2. Selection of responsive subjects. Participants in stage
hypnotism (all volunteers) are first “hypnotized” as a group.
Then, anyone who doesn’t yield to instructions is eliminated.
3. The hypnosis label disinhibits. Once a person has been
labeled “hypnotized,” she or he can sing, dance, act silly, or
whatever, without fear or embarrassment. On stage, being
“hypnotized” takes away personal responsibility for one’s
actions.
4. The hypnotist as a “director.” After volunteers loosen up
and respond to a few suggestions, they find that they are suddenly the stars of the show. Audience response to the antics
on stage brings out the “ham” in many people. All the “hypnotist” needs to do is direct the action.
5. The stage hypnotist uses tricks. Stage hypnosis is about
50 percent taking advantage of the situation and 50 percent
deception. One of the more impressive stage tricks is to rigidly suspend a person between two chairs. This is astounding
only because the audience does not question it. Anyone can
do it, as is shown in the photographs and instructions in
Figure 6.9. Try it!
•
197
To summarize, hypnosis is real, and it can significantly alter
private experience. Hypnosis is a useful tool in a variety of settings.
Nightclubs, however, are not one of these settings. Stage “hypnotists” entertain; they rarely hypnotize.
Meditation and Sensory Deprivation —
Chilling, the Healthy Way
Gateway Question: Do meditation and sensory deprivation have
any benefits?
Throughout history, meditation and sensory deprivation have
been widely used as a means of altering consciousness through
deep relaxation. Let’s see what they have in common and how they
differ.
Meditation
Meditation is a mental exercise used to alter consciousness. In
general, meditation focuses attention and interrupts the typical
flow of thoughts, worries, and analysis. People who use meditation
to reduce stress often report less daily physical tension and anxiety
(Andresen, 2000). Brain scans (positron emission tomography
[PET] and functional magnetic resonance imaging [fMRI]) reveal
changes in the activity of the frontal lobes during meditation,
which suggests that it may be a distinct state of consciousness
(Cahn & Polich, 2006; Farb et al., 2007).
Meditation takes two major forms. In concentrative meditation, you attend to a single focal point, such as an object, a
thought, or your own breathing. In contrast, mindfulness meditation is “open,” or expansive. In this case, you widen your attention
to embrace a total, nonjudgmental awareness of the world (Lazar,
2005). An example is losing all self-consciousness while walking in
the wilderness with a quiet and receptive mind. Although it may
not seem so, mindfulness meditation is more difficult to attain
than concentrative meditation. For this reason, we will discuss
concentrative meditation as a practical self-control method.
Performing Concentrative Meditation
How is concentrative meditation done? The basic idea is to sit still
and quietly focus on some external object or on a repetitive internal stimulus, such as your own breathing or humming (Blackmore,
2004). As an alternative, you can silently repeat a mantra (a word
used as the focus of attention in concentrative meditation). Typi-
Dennis Coon
Stage hypnosis Use of hypnosis to entertain; often, merely a
simulation of hypnosis for that purpose.
Meditation A mental exercise for producing relaxation or heightened
awareness.
6.9 Arrange three chairs as shown. Have someone recline as shown.
•AskFigure
him to lift slightly while you remove the middle chair. Accept the applause
Concentrative meditation Mental exercise based on attending to a
single object or thought.
gracefully! (Concerning hypnosis and similar phenomena, the moral, of course, is,
“Suspend judgment until you have something solid to stand on.”)
Mindfulness meditation Mental exercise based on widening attention
to become aware of everything experienced at any given moment.
198
CHAPTER 6
cal mantras are smooth, flowing sounds that are easily repeated. A
widely used mantra is the word “om.” A mantra could also be any
pleasant word or a phrase from a familiar song, poem, or prayer. If
other thoughts arise as you repeat a mantra, just return attention
to it as often as necessary to maintain meditation.
The Relaxation Response
The benefits of meditation include lowered heart rate, blood pressure, muscle tension, and other signs of stress (Lazar et al., 2000).
Medical researcher Herbert Benson believes that the core of
meditation is the relaxation response — an innate physiological
pattern that opposes your body’s fight-or-flight mechanisms. Benson feels, quite simply, that most of us have forgotten how to relax
deeply. People in his experiments learned to produce the relaxation response by following these instructions:
Sit quietly and comfortably. Close your eyes. Relax your muscles, beginning
at your feet and progressing up to your head. Relax them deeply. Become
aware of breathing through your nose. As you breathe out, say a word like
“peace” silently to yourself. Don’t worry about how successful you are in
relaxing deeply. Just let relaxation happen at its own pace. Don’t be surprised by distracting thoughts. When they occur, ignore them and continue
repeating “peace.” (Adapted from Benson, 1977; Lazar et al., 2000)
As a stress-control technique, meditation may be a good choice
for people who find it difficult to “turn off ” upsetting thoughts
when they need to relax. In one study, a group of college students
who received just 90 minutes of training in the relaxation response
experienced greatly reduced stress levels (Deckro et al., 2002). The
physical benefits of meditation include lowered heart rate, blood
pressure, muscle tension, and other signs of stress (Lazar et al.,
2000), as well as improved immune system activity (Davidson et al.,
2003).
According to Shauna Shapiro and Roger Walsh (2006), meditation has benefits beyond relaxation. Practiced regularly, meditation may foster mental well-being and positive mental skills such
as clarity, concentration, and calm. In this sense, meditation may
share much in common with psychotherapy. Indeed, research has
shown that mindfulness meditation relieves a variety of psychological disorders, from insomnia to anxiety disorders. It can
also reduce aggression and the illegal use of psychoactive drugs
(Shapiro & Walsh, 2006). Regular meditation may even help
people develop self-awareness and maturity (Travis, Arenander, &
DuBois, 2004).
Sensory Deprivation
The relaxation response can also be produced by brief sensory
deprivation. Sensory deprivation (SD) refers to any major reduction in the amount or variety of sensory stimulation.
What happens when stimulation is greatly reduced? A hint
comes from reports by prisoners in solitary confinement, arctic
explorers, high-altitude pilots, long-distance truck drivers, and
radar operators. When faced with limited or monotonous stimulation, people sometimes have bizarre sensations, dangerous lapses
Figure 6.10 A sensory isolation chamber. Small flotation tanks like the one
•pictured
have been used by psychologists to study the effects of mild sensory
deprivation. Subjects float in darkness and silence. The shallow body-temperature
water contains hundreds of pounds of Epsom salts so that subjects float near the
surface. Mild sensory deprivation produces deep relaxation.
in attention, and wildly distorted perceptions. Intense or prolonged SD is stressful and disorienting. Yet, oddly enough, brief
periods of sensory restriction can be very relaxing.
Psychologists have explored the possible benefits of sensory
restriction using small isolation tanks like the one pictured in Figure 6.10. An hour or two spent in a flotation tank, for instance, causes
a large drop in blood pressure, muscle tension, and other signs of
stress (van Dierendonck & Te Nijenhuis, 2005). Of course, it could
be argued that a warm bath has the same effect. Nevertheless, brief
sensory deprivation appears to be one of the surest ways to induce
deep relaxation (Suedfeld & Borrie, 1999).
Like meditation, sensory restriction may also help with more
than relaxation. Mild sensory deprivation can help people quit
smoking, lose weight, and reduce their use of alcohol and drugs
(van Dierendonck & Te Nijenhuis, 2005). Psychologist Peter
Suedfeld calls such benefits Restricted Environmental Stimulation Therapy (REST). Deep relaxation makes people more open
to suggestion, and sensory restriction interrupts habitual behavior
patterns. As a result, REST can “loosen” belief systems and make
it easier to change bad habits (Suedfeld & Borrie, 1999).
REST also shows promise as a way to stimulate creative thinking (Norlander, Bergman, & Archer, 1998). Other researchers
have reported that REST sessions can enhance performance in
skilled sports, such as gymnastics, tennis, basketball, darts, and
marksmanship (Druckman & Bjork, 1994; Norlander, Bergman,
& Archer, 1999). There is also evidence that REST can relieve
chronic pain and reduce stress (Bood et al., 2006). Clearly, there is
much yet to be learned from studying “nothingness.”
•
Summary
To summarize, research suggests that meditation and mild sensory
deprivation are ways to elicit the relaxation response. For many
people, sitting quietly and “resting” can be as effective. Similar
stress reduction occurs when people set aside time daily to engage
in other restful activities, such as muscle relaxation, positive daydreaming, and even leisure reading. However, if you are the type of
person who finds it difficult to ignore upsetting thoughts, then
concentrative meditation might be a good way to promote relaxation. Practiced regularly, meditation and REST may even help
improve overall mental health — something almost everyone could
use in our fast-paced society.
States of Consciousness
Did you “space out” anytime today? Most of us have occasional
moments of reduced awareness. Mindfulness is the opposite of
such mindless moments: It involves an open, nonjudgmental
awareness of current experience. In other words, mindfulness is
similar to the state that people who practice receptive meditation
are trying to achieve. A person who is mindful is fully present,
moment-by-moment. She or he is acutely aware of every thought,
emotion, or sensation, but does not judge it or react to it. The
person is fully “awake” and attuned to immediate reality.
Psychologists interested in positive mental states have begun to
study the effects of mindfulness. For example, cancer patients who
are taught mindfulness meditation have lower levels of distress and
a greater sense of well-being. Such benefits apply to healthy people,
too. In general, mindfulness is associated with self-knowledge and
well-being (Brown & Ryan, 2003). Anyone who has a tendency to
sleepwalk through life — and that’s most of us at times — would be
wise to be mindful of the value of mindfulness.
10. Regular meditators report lower levels of stress and a greater sense
of well-being. What other explanations must we eliminate before
this effect can be regarded as genuine?
Relate
How have your beliefs about hypnosis changed after reading the preceding section? Can you think of specific examples in which hypnosis was
misrepresented, such as in high school assemblies, stage acts, movies, or
TV dramas?
Various activities can produce the relaxation response. When do you
experience states of deep relaxation, coupled with a sense of serene
awareness? What similarities do these occurrences have to meditation?
Have you experienced any form of sensory restriction or sensory
deprivation? How did you react? Would you be willing to try REST in
order to break a bad habit?
Answers: 1. d 2. a 3. b 4. F 5. F 6. b 7. T 8. F 9. Most experiments on
hypnosis include a control group in which people are asked to simulate
being hypnotized. Without such controls, the tendency of subjects to
cooperate with experimenters makes it difficult to identify true hypnotic
effects. 10. Studies on the effects of meditation must control for the placebo effect and the fact that those who choose to learn meditation may
not be a representative sample of the general population.
Positive Psychology: Mindfulness and Well-Being
199
K N O W L E D GE B U I L D E R
Hypnosis, Meditation, and Sensory
Deprivation
RECITE
1. In Ernest Hilgard’s dissociative state theory of hypnosis, awareness is
split between normal consciousness and
a. disinhibition
b. autosuggestion
c. memory
d. the hidden observer
2. Tests of hypnotic susceptibility measure a person’s tendency to
respond to
a. suggestion
b. imagery rehearsal
c. stimulus control techniques
d. the activation-synthesis effect
3. Which of the following can most definitely be achieved with hypnosis?
a. unusual strength
b. pain relief
c. improved memory
d. sleep-like brainwaves
4. The focus of attention in concentrative meditation is “open,” or
expansive. T or F?
5. Mantras are words said silently to oneself to end a session of meditation. T or F?
6. Which terms do not belong together?
a. concentrative meditation — relaxation response
b. mindfulness meditation — mantra
c. sensory deprivation — REST
d. meditation — alter consciousness
7. The most immediate benefit of meditation appears to be its capacity
for producing the relaxation response. T or F?
8. Prolonged periods of extreme sensory deprivation lower anxiety and
induce deep relaxation. T or F?
REFLECT
Critical Thinking
9. What kind of control group would you need in order to identify the
true effects of hypnosis?
Drug-Altered Consciousness —
The High and Low of It
Gateway Question: What are the effects of the more commonly used
psychoactive drugs?
The most common way to alter human consciousness is to administer a psychoactive drug (a substance capable of altering attention,
judgment, memory, time sense, self-control, emotion, or perception). In fact, most Americans regularly use consciousness-altering
drugs (don’t forget that caffeine, alcohol, and nicotine are mildly
psychoactive). Psychoactive drugs alter consciousness by directly
influencing brain activity (Julien, 2005). (See “How Psychoactive
Drugs Affect the Brain.”) Many psychoactive drugs can be placed on
a scale ranging from stimulation to depression ( Figure 6.11). A
stimulant (upper) is a substance that increases activity in the body
and nervous system. A depressant (downer) does the reverse.
•
Relaxation response The pattern of internal bodily changes that
occurs at times of relaxation.
Sensory deprivation (SD) Any major reduction in the amount or
variety of sensory stimulation.
Restricted Environmental Stimulation Therapy (REST) A form of
sensory deprivation that results in a variety of psychological benefits.
Mindfulness A state of open, nonjudgmental awareness of current
experience.
Psychoactive drug A substance capable of altering attention, memory,
judgment, time sense, self-control, mood, or perception.
Stimulant (upper) A substance that increases activity in the body and
nervous system.
Depressant (downer) A substance that decreases activity in the body
and nervous system.
200
CHAPTER 6
Drug Effects
STIMULATION
Drug Groups
Death
Strychnine
Convulsions
Extreme nervousness,
tremors
Anxiety, palpitations
Amphetamines
Cocaine (large dose)
Feeling of well-being,
euphoria
Distortion of time
and space
Antidepressants
Cocaine (small dose)
Hallucinogens (LSD,
mescaline, marijuana)
Nicotine
Caffeine
Increased alertness
NEUTRAL AREA
Tranquilizers
Anxiety relief
Feeling of well-being,
euphoria
Loss of pain
Narcotics, barbiturates,
alcohol (small dose)
Narcotics (medium dose)
Barbiturates, alcohol
(medium dose)
Hypnotics
Narcotics, barbiturates,
alcohol (large dose)
Anesthetics
Drowsiness
Sleep
Loss of consciousness
Convulsions
Death
•
DEPRESSION
Figure 6.11 Spectrum and continuum of drug action. Many drugs can be
rated on a stimulation-depression scale according to their effects on the central
nervous system. Although LSD, mescaline, and marijuana are listed here, the
stimulation-depression scale is less relevant to these drugs. The principal characteristic of such hallucinogens is their mind-altering quality.
Because drugs that can ease pain, induce sleep, or end depression have a high potential for abuse, the more powerful psychoactive drugs are controlled substances (Goldberg, 2006). Nevertheless, more than 20 million Americans are currently illicit drug
users (SAMHSA, 2005). Drug abuse has been one of the most
persistent of all social problems in Western nations.
Why is drug abuse so common? People seek drug experiences for
many reasons, ranging from curiosity and a desire to belong to a
group, to a search for meaning or an escape from feelings of inadequacy. Many abusers turn to drugs in a self-defeating attempt to
cope with life. All the frequently abused drugs produce immediate
feelings of pleasure. The negative consequences follow much later.
This combination of immediate pleasure and delayed punishment
allows abusers to feel good on demand.
In time, of course, most of the pleasure goes out of drug abuse
and the abuser’s problems get worse. But if an abuser merely feels
better (however briefly) after taking a drug, drug taking can become
compulsive (Higgins, Heil, & Lussier, 2004). In contrast, people
who stop using drugs often say that they quit because the drawbacks had come to exceed the benefits (Toneatto et al., 1999).
The best predictors of adolescent drug use and abuse are drug
use by peers, parental drug use, delinquency, parental maladjust-
ment, poor self-esteem, social nonconformity, and stressful life
changes. One study found that adolescents who abuse drugs tend
to be maladjusted, alienated, impulsive, and emotionally distressed
(Masse & Tremblay, 1997). Antisocial behavior, school failure,
and risky sexual behavior are also commonly associated with drug
abuse (Ary et al., 1999). Such patterns make it clear that taking
drugs is a symptom, rather than a cause, of personal and social
maladjustment (Ksir, Hart, & Ray, 2006).
Drug Dependence
Another reason why drug abuse is so common is that taking most
psychoactive drugs tends to create dependencies. Once you get
started, it can be hard to stop. Drug dependence falls into two
broad categories. When a person compulsively uses a drug to
maintain bodily comfort, a physical dependence (addiction)
exists ( Julien, 2005). Addiction occurs most often with drugs that
cause withdrawal symptoms (physical illness that follows removal
of a drug). Withdrawal from drugs such as alcohol, barbiturates,
and opiates can cause violent flu-like symptoms of nausea, vomiting, diarrhea, chills, sweating, and cramps. Addiction is often
accompanied by a drug tolerance (reduced response to a drug).
This leads users to take larger and larger doses to get the desired
effect.
Persons who develop a psychological dependence feel that a
drug is necessary to maintain their comfort or well-being. Usually,
they intensely crave the drug and its rewarding qualities (Winger
et al., 2005). Psychological dependence can be just as powerful as
physical addiction. That’s why some psychologists define addiction as any compulsive habit pattern. By this definition, a person
who has lost control over drug use, for whatever reason, is addicted.
In fact, most people who answer yes to both of the following questions have an alcohol or drug problem and should seek professional help (Brown et al., 1997):
•
•
In the last year, did you ever drink or use drugs more than you
meant to?
Have you felt you wanted or needed to cut down on your
drinking or drug use in the last year?
Patterns of Abuse
Some drugs, of course, have a higher potential for abuse than
others. Heroin is certainly more dangerous than caffeine. However, this is only one side of the picture. It can be as useful to
classify drug-taking behavior as it is to rate drugs. For example,
some people remain social drinkers for life, whereas others
become alcoholics within weeks of taking their first drink (Robinson & Berridge, 2003). In this sense, drug use can be classified
as experimental (short-term use based on curiosity), socialrecreational (occasional social use for pleasure or relaxation), situational (use to cope with a specific problem, such as needing to
stay awake), intensive (daily use with elements of dependence), or
compulsive (intense use and extreme dependence). The last three
categories of drug taking tend to be damaging no matter what
drug is used.
States of Consciousness
201
B RAIN W AVES
How Psychoactive Drugs Affect the Brain
Psychoactive drugs influence the activity of
brain cells (Kalat, 2007). Typically, drugs imitate or alter the effects of neurotransmitters,
the chemicals that carry messages between
brain cells. Some drugs, such as Ecstasy,
amphetamines, and some antidepressants,
cause more neurotransmitters to be released,
increasing the activity of brain cells. Other
drugs, such as cocaine, slow the removal of
neurotransmitters after they are released. This
prolongs the action of transmitter chemicals
and typically has a stimulating effect. Other
drugs, such as nicotine and opiates, directly
stimulate brain cells by mimicking neurotransmitters. Another possibility is illustrated by
alcohol and tranquilizers. These drugs affect
certain types of brain cells that cause relaxation and relieve anxiety. Some drugs fill
receptor sites on brain cells and block incoming messages. Other possibilities also exist,
which is why drugs can have such a wide variety of effects on the brain (Julien, 2005).
Nearly all addictive drugs stimulate the
brain’s reward circuitry, producing feelings
of pleasure (Kalat, 2007). In particular, addictive drugs stimulate a brain region called the
nucleus accumbens to release the neurotransmitter dopamine, which results in intensified
feelings of pleasure ( Figure 6.12). As one
expert put it, addictive drugs fool brain-reward
pathways. “As a result, the reward pathway
signals, ‘That felt good. Let’s do it again. Let’s
remember exactly how we did it.’” This creates
a compulsion to repeat the drug experience.
It’s the hook that eventually snares the addict
•
Dopamine
projections
to prefrontal
cortex
(Restak, 2001). In the end, the addictive drug
physically changes the brain’s reward circuitry, making it even harder for the addict
to overcome his or her addiction (Robinson
& Berridge, 2003). Adolescents are especially
susceptible to addiction because brain systems that restrain their risk-taking are not as
mature as those that reward pleasure seeking
(Chambers, Taylor, & Potenza, 2003).
Figure 6.12 Addictive
•drugs
increase dopamine
activity in the medial forebrain bundle and the nucleus
accumbens, stimulating the
frontal cortex and giving
rise to intensified feelings of
pleasure.
Nucleus
accumbens
Medial forebrain bundle
(a path of axons that
release dopamine)
Drugs of Abuse
•
Note in Table 6.4 that the drugs most likely to lead to physical
dependence are alcohol, amphetamines, barbiturates, cocaine,
codeine, heroin, methadone, morphine, and tobacco (nicotine).
Using any of the drugs listed in Table 6.4 can result in psychological dependence. Note too that people who take drugs intravenously are at high risk for developing hepatitis and AIDS. The
discussion that follows focuses on the drugs most often abused by
students. A more complete summary of frequently abused psychoactive drugs is given in Table 6.4.
•
•
bridges
Area in midbrain
sion. Today, the main legitimate medical use of amphetamines is
to treat childhood hyperactivity and overdoses of depressant drugs.
Illicit use of amphetamines is widespread, however, especially by
people seeking to stay awake and by those who think drugs can
improve mental or physical performance (Iversen, 2006).
Methamphetamine is a more potent variation of amphetamine.
It can be snorted, injected, or eaten. Of the various types of
amphetamine, methamphetamine has created the largest drug
problem. “Bergs,” “glass,” “meth,” or “crystal,” as it is known on the
street, can be made cheaply in backyard labs and sold for massive
profits. In addition to ruining lives through addiction, it has
fueled a violent criminal subculture.
See Chapter 11, pages 379–380, for more information about
AIDS.
Uppers — Amphetamines, Cocaine,
MDMA, Caffeine, Nicotine
Amphetamines are synthetic stimulants. Common street names
for amphetamine are “speed,” “bennies,” “dexies,” “go,” and “uppers.”
These drugs were once widely prescribed for weight loss or depres-
Physical dependence (addiction) Physical addiction, as indicated by
the presence of drug tolerance and withdrawal symptoms.
Withdrawal symptoms Physical illness and discomfort following the
withdrawal of a drug.
Drug tolerance A reduction in the body’s response to a drug.
Psychological dependence Drug dependence that is based primarily
on emotional or psychological needs.
202
CHAPTER 6
Table 6.4
• Comparison of Psychoactive Drugs
Name
Classification
Medical Use
Usual Dose
Duration of Effect
Alcohol
Sedative-hypnotic
Solvent, antiseptic
Varies
1–4 hours
Amphetamines
Stimulant
Relief of mild depression, control of narcolepsy and hyperactivity
2.5–5 milligrams
4 hours
Barbiturates
Sedative-hypnotic
Sedation, relief of high blood pressure,
anticonvulsant
50–100 milligrams
4 hours
Benzodiazepines
Anxiolytic (antianxiety drug)
Tranquilizer
2–100 milligrams
10 minutes–8 hours
Caffeine
Stimulant
Counteract depressant drugs, treatment
of migraine headaches
Varies
Varies
Cocaine
Stimulant, local anesthetic
Local anesthesia
Varies
Varied, brief periods
Codeine
Narcotic
Ease pain and coughing
30 milligrams
4 hours
GHB
Sedative-hypnotic
Experimental treatment of narcolepsy,
alcoholism
1–3 grams (powder)
1–3 hours
Heroin
Narcotic X
Pain relief
Varies
4 hours
LSD
Narcotic
Experimental study of mental function,
alcoholism
100–500 milligrams
10 hours
Marijuana (THC)
Relaxant, euphoriant; in high
doses, hallucinogen
Treatment of glaucoma and side effects of
chemotherapy
1–2 cigarettes
4 hours
MDMA
Stimulant/hallucinogen
None
125 milligrams
4–6 hours
Mescaline
Hallucinogen
None
350 micrograms
12 hours
Methadone
Narcotic
Pain relief
10 milligrams
4–6 hours
Morphine
Narcotic
Pain relief
15 milligrams
6 hours
PCP
Anesthetic
None
2–10 milligrams
4–6 hours, plus 12-hour
recovery
Psilocybin
Hallucinogen
None
25 milligrams
6–8 hours
Tobacco
(nicotine)
Stimulant
Emetic (nicotine)
Varies
Varies
Question marks indicate conflict of opinion. It should be noted that illicit drugs are frequently adulterated and thus pose unknown hazards to the user.
Amphetamines rapidly produce a drug tolerance. Most abusers
end up taking ever-larger doses to get the desired effect. Eventually, some users switch to injecting methamphetamine directly
into the bloodstream. True speed freaks typically go on binges lasting several days, after which they “crash” from lack of sleep and
food.
Abuse
How dangerous are amphetamines? Amphetamines pose many
dangers. Large doses can cause nausea, vomiting, extremely high
blood pressure, fatal heart attacks, and disabling strokes. It is
important to realize that amphetamines speed up the use of the
body’s resources; they do not magically supply energy. After an
amphetamine binge, people suffer from crippling fatigue, depression, confusion, uncontrolled irritability, and aggression. Repeated
amphetamine use damages the brain. Amphetamines can also
cause amphetamine psychosis, a loss of contact with reality. Affected
users have paranoid delusions that someone is out to get them.
Acting on these delusions, they may become violent, resulting in
suicide, self-injury, or injury to others (Iversen, 2006).
A potent smokable form of crystal methamphetamine has
added to the risks of stimulant abuse. This drug, known as “ice” on
the street, is highly addictive. Like “crack,” the smokable form of
cocaine, it produces an intense high. But also like crack (discussed
in a moment), crystal methamphetamine leads very rapidly to
compulsive abuse and severe drug dependence.
States of Consciousness
203
Physical
Dependence
Potential
Psychological
Dependence
Potential
Organic
Damage
Potential
Effects Sought
Long-term Symptoms
Sense alteration, anxiety reduction,
sociability
Cirrhosis, toxic psychosis, neurologic damage,
addiction
Yes
Yes
Yes
Alertness, activeness
Loss of appetite, delusions, hallucinations, toxic
psychosis
Yes
Yes
Yes
Anxiety reduction, euphoria
Addiction with severe withdrawal symptoms,
possible convulsions, toxic psychosis
Yes
Yes
Yes
Anxiety relief
Irritability, confusion, depression, sleep disorders
Yes
Yes
No, but can
affect fetus
Wakefulness, alertness
Insomnia, heart arrhythmias, high blood pressure
No?
Yes
Yes
Excitation, talkativeness
Depression, convulsions
Yes
Yes
Yes
Euphoria, prevent withdrawal
discomfort
Addiction, constipation, loss of appetite
Yes
Yes
No
Intoxication, euphoria, relaxation
Anxiety, confusion, insomnia, hallucinations,
seizures
Yes
Yes
No?
Euphoria, prevent withdrawal
discomfort
Addiction, constipation, loss of appetite
Yes
Yes
No*
Insightful experiences, exhilaration,
distortion of senses
May intensify existing psychosis, panic reactions
No
No?
No?
Relaxation; increased euphoria,
perceptions, sociability
Possible lung cancer, other health risks
Yes
Yes
Yes?
Excitation, euphoria
Personality change, hyperthermia, liver damage
No
Yes
Yes
Insightful experiences, exhilaration,
distortion of senses
May intensify existing psychosis, panic reactions
No
No?
No?
Prevent withdrawal discomfort
Addiction, constipation, loss of appetite
Yes
Yes
No
Euphoria, prevent withdrawal
discomfort
Addiction, constipation, loss of appetite
Yes
Yes
No*
Euphoria
Unpredictable behavior, suspicion, hostility,
psychosis
Debated
Yes
Yes
Insightful experiences, exhilaration,
distortion of senses
May intensify existing psychosis, panic reactions
No
No?
No?
Alertness, calmness, sociability
Emphysema, lung cancer, mouth and throat
cancer, cardiovascular damage, loss of appetite
Yes
Yes
Yes
*Persons who inject drugs under nonsterile conditions run a high risk of contracting AIDS, hepatitis, abscesses, or circulatory disorders.
Cocaine
Cocaine (“coke,” “snow,” “blow,” “snuff ”) is a powerful central nervous system stimulant extracted from the leaves of the coca plant.
Cocaine produces feelings of alertness, euphoria, well-being, power,
boundless energy, and pleasure ( Julien, 2005). At the turn of the
twentieth century, dozens of nonprescription potions and cure-alls
contained cocaine. It was during this time that Coca-Cola was
indeed the “real thing.” From 1886 until 1906, when the U.S. Pure
Food and Drug Act was passed, Coca-Cola contained cocaine
(which has since been replaced with caffeine).
How does cocaine differ from amphetamines? The two are very
much alike in their effects on the central nervous system. The
main difference is that amphetamine lasts several hours; cocaine is
snorted and quickly metabolized, so its effects last only about 15
to 30 minutes.
Abuse
How dangerous is cocaine? Cocaine’s capacity for abuse and social
damage rivals that of heroin. When rats and monkeys are given
free access to cocaine, they find it irresistible. Many, in fact, end up
dying of convulsions from self-administered overdoses of the drug.
Even casual or first-time users risk having convulsions, a heart
attack, or a stroke (Lacayo, 1995). Cocaine increases the chemical
messengers dopamine (DOPE-ah-meen) and noradrenaline (norah-DREN-ah-lin). Noradrenaline arouses the brain, and dopamine produces a “rush” of pleasure. This combination is so power-
204
CHAPTER 6
National Library of Medicine
cells to release extra amounts of serotonin. The physical effects of
MDMA include dilated pupils, elevated blood pressure, jaw
clenching, loss of appetite, and elevated body temperature (Braun,
2001). Although some users believe that Ecstasy increases sexual
pleasure, it diminishes sexual performance, impairing erection in
40 percent of men and retarding orgasm in both men and women.
(Zemishlany, Aizenberg, & Weizman, 2001).
Cocaine was the main ingredient in many nonprescription elixirs before the turn
of the twentieth century. Today cocaine is recognized as a powerful and dangerous drug. Its high potential for abuse has damaged the lives of countless users.
fully rewarding that cocaine users run a high risk of becoming
compulsive abusers (Ridenour et al., 2005).
A person who stops using cocaine does not experience heroinlike withdrawal symptoms. Instead, the brain adapts to cocaine
abuse in ways that upset its chemical balance, causing depression
when cocaine is withdrawn. First, there is a jarring “crash” of
mood and energy. Within a few days, the person enters a long
period of fatigue, anxiety, paranoia, boredom, and anhedonia
(an-he-DAWN-ee-ah: an inability to feel pleasure). Before long,
the urge to use cocaine becomes intense. So, although cocaine
does not fit the classic pattern of addiction, it is ripe for compulsive abuse. Even a person who gets through withdrawal may crave
cocaine months or years later (Withers et al., 1995). If cocaine
were cheaper, 9 out of 10 users would progress to compulsive
abuse. In fact, rock cocaine (“crack,” “rock,” or “roca”), which is
cheaper, produces very high abuse rates. Here are some signs of
cocaine abuse:
•
•
•
Compulsive use. If cocaine is available — say, at a party — you
can’t say no to it.
Loss of control. Once you have had some cocaine, you will keep
using it until you are exhausted or the cocaine is gone.
Disregarding consequences. You don’t care if the rent gets paid,
your job is endangered, your lover disapproves, or your health
is affected, you’ll use cocaine anyway.
Anyone who thinks she or he has a cocaine problem should
seek advice at a drug clinic or a Cocaine Anonymous meeting.
Although quitting cocaine is extremely difficult, three out of four
abusers who remain in treatment do succeed in breaking their coke
dependence (Simpson et al., 1999; Sinha et al., 2006).
MDMA (“Ecstasy”)
The drug MDMA (methylenedioxymethamphetamine, or
“Ecstasy”) is also chemically similar to amphetamine. In addition
to producing a rush of energy, users say it makes them feel closer
to others and heightens sensory experiences. Ecstasy causes brain
Abuse
Ecstasy use in North America has declined slightly from a peak
around 2002, perhaps because of widespread negative publicity.
Regardless, every year more than half a million Americans try
Ecstasy for the first time (SAMHSA, 2005). Every year, emergency room doctors see many MDMA cases, including MDMArelated deaths. Some of these incidents are caused by elevated body
temperature (hyperthermia) or heart arrhythmias, which can lead
to collapse. Ecstasy users at “rave” parties try to prevent overheating by drinking water to cool themselves. This may help to a small
degree, but the risk of fatal heat exhaustion is real. MDMA can
also cause severe liver damage, which can be fatal (Braun, 2001). In
addition, Ecstasy users are more likely to abuse alcohol and other
drugs, to neglect studying, to party excessively, and to engage in
risky sex (Strote, Lee, & Wechsler, 2002). Ironically, Ecstasy use at
“rave” parties actually does intensify the impact of the music. We
say ironically because the end result is often overstimulation of the
brain, which can result in a “rebound” depression (Michelangelo
et al., 2006).
It may take another decade before Ecstasy’s full impact on
health emerges. For now, we know that repeated use of MDMA
damages serotonergic brain cells. This damage lasts for years. It
leads to feelings of anxiety or depression that can persist for
months after a person stops taking Ecstasy. In addition, heavy
users typically do not perform well in tests of learning and memory and show signs of underlying brain damage (Quednow et al.,
2006). Despite its street name, Ecstasy may be a ticket to agony for
many users (Iversen, 2006; Kuhn & Wilson, 2001).
Caffeine
Caffeine is the most frequently used psychoactive drug in North
America. (And that’s not counting Seattle!) Caffeine stimulates
the brain by blocking chemicals that normally inhibit or slow
nerve activity ( Julien, 2005). Its effects become apparent with
doses as small as 50 milligrams, the amount found in about onehalf cup of brewed coffee. Physically, caffeine causes sweating,
talkativeness, tinnitus (ringing in the ears), and hand tremors
(Nehlig, 2004). Psychologically, caffeine suppresses fatigue or
drowsiness and increases feelings of alertness (Wesensten et al.,
2002). Some people have a hard time starting a day (or writing
another paragraph) without it.
How much caffeine did you consume today? It is common to
think of coffee as the major source of caffeine, but there are many
others. Caffeine is found in tea, many soft drinks (especially
colas), chocolate, and cocoa. More than 2,000 nonprescription
States of Consciousness
205
drugs also contain caffeine, including stay-awake pills, cold remedies, and many name-brand aspirin products.
Are there any serious drawbacks to using caffeine? Overuse of caffeine may result in an unhealthy dependence known as caffeinism.
Insomnia, irritability, loss of appetite, chills, racing heart, and elevated body temperature are all signs of caffeinism. Many people
with these symptoms drink 15 or 20 cups of coffee a day. However,
even at lower dosages, caffeine can intensify anxiety and other
psychological problems (Hogan, Hornick, & Bouchoux, 2002).
Caffeine poses a variety of health risks. Caffeine encourages the
growth of breast cysts in women, and it may contribute to bladder
cancer, heart problems, and high blood pressure. Pregnant women
should consider giving up caffeine entirely because of a suspected
link between caffeine and birth defects. Pregnant women who
consume as little as 2 cups coffee a day increase the risk of having
a miscarriage (Cnattingius et al., 2000).
It is customary to think that caffeine is not a drug. But as few as
2.5 cups of coffee a day (or the equivalent) can be a problem.
People who consume even such modest amounts may experience
anxiety, depression, fatigue, headaches, and flu-like symptoms
during withdrawal ( Juliano & Griffiths, 2004). About half of all
caffeine users show some signs of dependence (Hughes et al.,
1998). It is wise to remember that caffeine is a drug and use it in
moderation.
Nicotine
Nicotine is a natural stimulant found mainly in tobacco. Next to
caffeine and alcohol, it is the most widely used psychoactive drug
( Julien, 2005).
How does nicotine compare with other stimulants? Nicotine is a
potent drug. It is so toxic that it is sometimes used to kill insects!
In large doses it causes stomach pain, vomiting and diarrhea, cold
sweats, dizziness, confusion, and muscle tremors. In very large
doses, nicotine may cause convulsions, respiratory failure, and
death. For a nonsmoker, 50 to 75 milligrams of nicotine taken in a
single dose could be lethal. (Chain-smoking about 17 to 25 cigarettes will produce this dosage.) Most first-time smokers get sick
on one or two cigarettes. In contrast, regular smokers build a tolerance for nicotine. A heavy smoker may inhale 40 cigarettes a day
without feeling ill.
Abuse
How addictive is nicotine? A vast array of evidence confirms that
nicotine is very addictive (Spinella, 2005). The average age of first
use is 15, and it takes about a year before dependence sets in
(Baker, Brandon, & Chassin, 2004). Among regular smokers who
are 15 to 24 years old, 60 percent are addicted (Breslau et al.,
2001). For many smokers, withdrawal from nicotine causes headaches, sweating, cramps, insomnia, digestive upset, irritability, and
a sharp craving for cigarettes (NIDA, 2006). These symptoms may
last from 2 to 6 weeks and may be worse than heroin withdrawal.
The Everett Collection
Abuse
Actress and comedienne Lily Tomlin, here shown portraying one of her comedic
characters, Ernestine, once took up smoking for a role in a movie (Shadows and Fog)
and developed a 4-pack-a-day habit. As Tomlin’s experience shows, the best way to
avoid developing a nicotine addiction is to not begin smoking in the first place.
Indeed, relapse patterns are nearly identical for alcoholics, heroin
addicts, cocaine abusers, and smokers who try to quit (Stolerman
& Jarvis, 1995). Up to 90 percent of people who quit smoking
relapse within a year, and 20 percent relapse even after 2 years of
abstinence (Krall, Garvey, & Garcia, 2002).
Impact on Health
How serious are the health risks of smoking? If you think smoking
is harmless, or that there’s no connection between smoking and
cancer, you’re kidding yourself. A burning cigarette releases a large
variety of potent carcinogens (car-SIN-oh-jins: cancer-causing substances). According to the U.S. Surgeon General (USDHHS,
2004), “smoking harms nearly every organ of the body,” leading to
an increased risk of many cancers (such as lung cancer), cardiovascular diseases (such as stroke), respiratory diseases (such as chronic
bronchitis), and reproductive disorders (such as decreased fertility). Together, these health risks combine to reduce the life expectancy of the average smoker by 10 to 15 years. (Skeptics please
note: Wayne McLaren, who portrayed the rugged “Marlboro
Man” in cigarette ads, died of lung cancer at age 51.) More people
die every year from tobacco use than from motor vehicle injuries,
murders, suicides, alcohol use, illegal drug use, and AIDS combined (NCCDPHP, 2004).
Anhedonia An inability to feel pleasure.
Caffeinism Excessive consumption of caffeine, leading to dependence
and a variety of physical and psychological complaints.
CHAPTER 6
© Clive Goddard/www.CartoonStock.com
206
By the way, urban cowboys and Skol bandits, the same applies
to chewing tobacco and snuff. A 30-minute exposure to one pinch
of smokeless tobacco is equivalent to smoking three or four cigarettes. Along with all the health risks of smoking, users of smokeless tobacco also run a higher risk of developing oral cancer
(American Lung Association, 2006).
Smokers don’t just risk their own health; they also endanger
those who live and work nearby. Secondary smoke causes about
3,000 lung cancer deaths and as many as 62,000 heart disease
deaths each year in the United States alone. It is particularly irresponsible of smokers to expose young children, who are especially
vulnerable, to secondhand smoke (American Lung Association,
2006).
Quitting Smoking
Is it better for a person to quit smoking abruptly or taper down
gradually? Most people try to quit by themselves. Some try to quit
cold turkey, whereas others try to taper down gradually. Although
going cold turkey has its advocates, gradually quitting works better
for more people.
Going cold turkey makes quitting an all-or-nothing proposition. Smokers who smoke even one cigarette after “quitting forever” tend to feel they’ve failed. Many figure they might just as
well resume smoking. Those who quit gradually accept that success may take many attempts, spread over several months. If you
are going to quit by going cold turkey, you will have a better
chance of success if you decide to quit now rather than at some
time in the future (West & Sohal, 2006).
The best way to taper off is scheduled gradual reduction (Riley et
al., 2002). There are many ways in which smoking can be gradually
reduced. For example, the smoker can (1) delay having a first cigarette in the morning and then try to delay a little longer each day,
(2) gradually reduce the total number of cigarettes smoked each
day, or (3) quit completely, but for just 1 week, then quit again, a
week at a time, for as many times as necessary to make it stick.
Deliberately scheduling the gradually stretching of time periods
between cigarettes is a key part of this program. Scheduled smoking apparently helps people learn to cope with the urge to smoke.
As a result, people using this method are more likely remain permanent nonsmokers than people using other approaches (Cinciripini, Wetter, & McClure, 1997).
Whatever approach is taken, quitting smoking is not easy
(Abrams et al., 2003). Many people find that using nicotine
patches or gum helps them get through the withdrawal period
(Shiffman et al., 2006). Also, as we have noted, anyone trying to
quit should be prepared to make several attempts before succeeding. But the good news is tens of millions of people have quit.
bridges
Behavioral self-management techniques can be very useful for
breaking habits such as smoking. See Chapter 7, pages
247–248, and Chapter 15, pages 522–526.
Downers — Sedatives, Tranquilizers,
and Alcohol
The most widely used downers, or depressant drugs, are barbiturates, GHB, benzodiazepine (ben-zoe-die-AZ-eh-peen) tranquilizers, and alcohol. These drugs are much alike in their effects. In
fact, barbiturates and tranquilizers are sometimes referred to as
“solid alcohol.” Let’s examine the properties of each.
Barbiturates
Barbiturates are sedative drugs that depress brain activity. Common barbiturates include amobarbital, pentobarbital, secobarbital, and Tuinal. On the street they are known as “downers,” “blue
heavens,” “yellow jackets,” “lows,” “goof balls,” “reds,” “pink ladies,”
“rainbows,” or “tooies.” Medically, barbiturates are used to calm
patients or to induce sleep. At mild dosages, barbiturates have an
effect similar to alcohol intoxication. Higher dosages can cause
severe mental confusion or even hallucinations. Barbiturates are
often taken in excess amounts because a first dose may be followed
by others, as the user becomes uninhibited or forgetful. Overdoses
first cause a loss of consciousness. Then they severely depress brain
centers that control heartbeat and breathing. The result is death
(McKim, 2007).
GHB
Would you swallow a mixture of degreasing solvent and drain
cleaner to get high? Apparently, a lot of people would. A miniepidemic of GHB (gamma-hydroxybutyrate) use has taken place in
recent years, especially at nightclubs and raves. GHB (“goop,”
“scoop,” “max,” “Georgia Home Boy”) is a central nervous system
depressant that relaxes and sedates the body. Users describe its
effects as being similar to alcohol. Mild GHB intoxication tends to
produce euphoria, a desire to socialize, and a mild loss of inhibi-
States of Consciousness
tions. GHB’s intoxicating effects typically last 3 to 4 hours, depending on the dosage.
Abuse
At lower dosages, GHB can relieve anxiety and produce relaxation. However, as the dose increases, its sedative effects may result
in nausea, a loss of muscle control, and either sleep or a loss of
consciousness. Potentially fatal doses of GHB are only three times
the amount typically taken by users. This narrow margin of safety
has led to numerous overdoses, especially when GHB was combined with alcohol. An overdose causes coma, breathing failure,
and death. Also, GHB inhibits the gag reflex, so some users choke
to death on their own vomit.
In 2000, the U.S. government classified GHB as a controlled
substance, making its possession a felony. Clinical evidence increasingly suggests that GHB is addictive and a serious danger to users.
Two out of three frequent users have lost consciousness after taking GHB. Heavy users who stop taking GHB have withdrawal
symptoms that include anxiety, agitation, tremor, delirium, and
hallucinations (Miotto et al., 2001).
As if the preceding weren’t enough reason to be leery of GHB,
here’s one more to consider: GHB is often manufactured in homes
with recipes and ingredients purchased on the Internet. As mentioned earlier, it can be produced by combining degreasing solvent
with drain cleaner (Falkowski, 2000). If you want to degrease your
brain, GHB will do the trick.
Tranquilizers
A tranquilizer is a drug that lowers anxiety and reduces tension.
Doctors prescribe benzodiazepine tranquilizers to alleviate nervousness and stress. Valium is the best-known drug in this family;
others are Xanax, Halcion, and Librium. Even at normal dosages
these drugs can cause drowsiness, shakiness, and confusion. When
used at too high a dosage or for too long, benzodiazepines are
addictive (McKim, 2007).
A drug sold under the trade name Rohypnol (ro-HIP-nol) has
added to the problem of tranquilizer abuse. This drug, which is
related to Valium, is cheap and 10 times more potent. It lowers
inhibitions and produces relaxation or intoxication. Large doses
induce short-term amnesia and sleep. “Roofies,” as they are known
on the street, are odorless and tasteless. They have been used to
spike drinks, which are given to the unwary. Victims of this “date
rape” drug are then sexually assaulted or raped while they are
unconscious. (Be aware, however, that drinking too much alcohol
is by far the most common prelude to rape.)
Abuse
Repeated use of barbiturates can cause physical dependence. Some
abusers suffer severe emotional depression that may end in suicide.
Similarly, when tranquilizers are used at too high a dosage or for
too long, addiction can occur. Many people have learned the hard
way that their legally prescribed tranquilizers are as dangerous as
many illicit drugs (McKim, 2007).
207
Combining barbiturates or tranquilizers with alcohol is especially risky. When mixed, the effects of both drugs are multiplied
by a drug interaction (one drug enhances the effect of another).
Drug interactions are responsible for many hundreds of fatal drug
overdoses every year (Goldberg, 2006). All too often, depressants
are gulped down with alcohol or added to a spiked punch bowl.
This is the lethal brew that left a young woman named Karen Ann
Quinlan in a coma that lasted 10 years, ending with her death. It is
no exaggeration to restate that mixing depressants with alcohol
can be deadly.
Alcohol
Alcohol is the common name for ethyl alcohol, the intoxicating
element in fermented and distilled liquors. Contrary to popular
belief, alcohol is not a stimulant. The noisy animation at drinking
parties is due to alcohol’s effect as a depressant. As Figure 6.13
shows, small amounts of alcohol reduce inhibitions and produce
feelings of relaxation and euphoria. Larger amounts cause evergreater impairment of the brain until the drinker loses consciousness. Alcohol is also not an aphrodisiac. Rather than enhancing
sexual arousal, it usually impairs performance, especially in males.
As William Shakespeare observed long ago, drink “provokes the
desire, but it takes away the performance.”
Some people become aggressive and want to argue or fight when
they are drunk. Others become relaxed and friendly. How can the
same drug have such different effects? When a person is drunk,
thinking and perception become dulled or shortsighted, a condition that has been called alcohol myopia (my-OH-pea-ah). Only
the most obvious and immediate stimuli catch a drinker’s attention. Worries and “second thoughts” that would normally restrain
behavior are banished from the drinker’s mind. That’s why many
behaviors become more extreme when a person is drunk. On college campuses, drunken students tend to have accidents, get into
fights, sexually assault others, or engage in risky sex. They also
destroy property and disrupt the lives of students who are trying
to sleep or study (Brower, 2002)
•
Abuse
Alcohol, the world’s favorite depressant, breeds our biggest drug
problem. More than 20 million people in the United States and
Canada have serious drinking problems. One American dies every
20 minutes in an alcohol-related car crash. The level of alcohol
abuse among adolescents and young adults is alarming. Of
18-year-olds, 15 percent are heavy drinkers and 40 percent have
engaged in binge drinking (SAMHSA, 2005). Binge drinking is
Tranquilizer A drug that lowers anxiety and reduces tension.
Drug interaction A combined effect of two drugs that exceeds the
addition of one drug’s effects to the other.
Alcohol myopia Shortsighted thinking and perception that occurs
during alcohol intoxication.
Binge drinking Consuming five or more drinks in a short time (four
drinks for women).
208
CHAPTER 6
•
Figure 6.13 The behavioral effects of alcohol
are related to blood alcohol content and the resulting suppression of higher mental function. Arrows
indicate the typical threshold for legal intoxication in
the United States. (From Jozef Cohen, Eyewitness Series in
Psychology, SS 7, p. 44. Copyright © 1970 by Rand McNally and
Company. Reprinted by permission of the author’s estate.)
Alcohol Consumed
Neural Representation
2 ounces
90 proof whiskey
Affects higher nervous centers;
drinker loses inhibitions, forgoes
conventions and courtesies,
relaxes
.05% blood alcohol
6 ounces
90 proof whiskey
Affects deeper motor areas;
drinker staggers, has slurred
speech, is overconfident, acts on
impulse
.15% blood alcohol
defined as downing five or more drinks in
a short time (four drinks for women).
Apparently, many students think it’s entertaining to get completely wasted and throw
up on their friends. However, binge drinking is a serious sign of alcohol abuse. It is
responsible for 1,400 college student
deaths each year and thousands of trips to
the ER (Wechsler et al., 2002).
Binge drinking is of special concern
because the brain continues to develop
into the early 20s. Research has shown that
teenagers and young adults who drink too
much may lose as much as 10 percent of
their brain power — especially their memory capacity (Brown et al., 2000). Such
losses can have a long-term impact on a
person’s chances for success in life. In short,
getting drunk is a slow but sure way to get
stupid (Wechsler & Wuethrich, 2002).
At Risk
Behavioral Effect
10 ounces
90 proof whiskey
Affects emotional centers of
midbrain; drinker has impaired
motor reactions and unsteady gait;
sensations are distorted; drinker
tends to see double, to fall asleep
.25% blood alcohol
16 ounces
90 proof whiskey
Affects sensory area of
cerebellum; senses are dulled;
drinker is in stupor
.4% blood alcohol
24 ounces
90 proof whiskey
.6% blood alcohol
Affects perceptual areas; drinker
loses consciousness; only
functions of breathing and
heartbeat remain
32 ounces
90 proof whiskey
Affects entire brain; heartbeat and
respiration stop; death
.8% blood alcohol
Children of alcoholics and those who have
other relatives who abuse alcohol are at
greater risk for becoming alcohol abusers
themselves. The increased risk appears to be partly genetic. It is
based on the fact that some people have stronger cravings for alcohol after they drink (Hutchison et al., 2002). Women also face
some special risks. For one thing, alcohol is absorbed faster and
metabolized more slowly by women’s bodies. As a result, women
get intoxicated from less alcohol than men do. Women who drink
are also more prone to liver disease, osteoporosis, and depression.
As few as three drinks a week may increase a woman’s risk of breast
cancer by 50 percent.
Positive reinforcement — drinking for pleasure — motivates
most people who consume alcohol. What sets alcohol abusers
apart is that they also drink to cope with negative emotions, such
as anxiety and depression. That’s why alcohol abuse increases with
the level of stress in people’s lives. People who drink to relieve bad
feelings are at great risk of becoming alcoholics (Kenneth, Carpenter, & Hasin, 1998).
Recognizing Problem Drinking
What are the signs of alcohol abuse? Because alcohol abuse is such a
common problem, it is important to recognize the danger signals.
If you can answer yes to even one of the following questions, you
may have a problem with drinking (adapted from the College
Alcohol Problems Scale, revised; Maddock et al., 2001):
As a Result of Drinking Alcoholic Beverages I . . .
1. engaged in unplanned sexual activity.
2. drove under the influence.
3. did not use protection when engaging in sex.
4. engaged in illegal activities associated with drug use.
5. felt sad, blue, or depressed.
6. was nervous or irritable.
7. felt bad about myself.
8. had problems with appetite or sleeping.
States of Consciousness
Table 6.5
209
• Drinking in Moderation
Dougie Wallace/Alamy
Approximate Number of Drinks per Hour to Stay Below 0.05
Blood Alcohol*
Your Weight
(pounds)
Male
Female
100
0.75
0.60
120
1.00
0.75
140
1.25
0.90
160
1.30
1.00
180
1.50
1.10
200
1.60
1.20
220
1.80
1.35
One drink 12 ounces beer, 4 ounces wine, 2.5 ounces brandy, or 1.25 ounces 80 proof liquor.
*Table entries are approximate, owing to individual differences in metabolism, recency of meals,
and other factors. Estimates are from tables prepared by Vogler and Bartz (1982, 1992).
Binge drinking and alcohol abuse have become serious problems among college
students. Many alcohol abusers regard themselves as “moderate” drinkers, which
suggests that they are in denial about how much they actually drink (Grant &
Dawson, 1997).
3. Limit drinking primarily to the first hour of a social event or party. Pace
your drinking using the information from Table 6.5.
4. Practice how you will politely but firmly refuse drinks.
5. Learn how to relax, meet people, and socialize without relying on alcohol.
•
Perhaps the simplest way to identify problem drinkers is to ask
a single question: “When was the last time you had more than five
drinks (four for women) in a day?” Eighty-six percent of the people who answer “less than 3 months ago” are alcohol abusers (Williams & Vinson, 2001).
Moderated Drinking
Almost everyone has been to a party spoiled by someone who
drank too much too fast. Those who avoid overdrinking have a
better time, and so do their friends. But how do you avoid drinking too much? After all, as one wit once observed, “The conscience
dissolves in alcohol.” Psychologists Roger Vogler and Wayne Bartz
(1982, 1992) provide a partial answer.
Vogler and Bartz observe that drinking makes you feel good
while blood alcohol is rising and remains below a level of about
0.05. In this range, people feel relaxed, euphoric, and sociable. At
higher levels they go from moderately intoxicated to thoroughly
drunk. Later, as blood alcohol begins to fall, those who overdrink
become sick and miserable. Table 6.5 shows the approximate
amount per hour that can be consumed without exceeding the
0.05 blood alcohol level. (Even at this level, driving may be
impaired.) By pacing themselves, those who choose to drink can
remain comfortable, pleasant, and coherent during a long social
event. In short, if you drink, it might be wise to learn your “magic”
number from Table 6.5.
It takes skill to regulate drinking in social situations, where the
temptation to drink can be strong. If you choose to drink, here are
some guidelines that may be helpful:
•
•
Paced Drinking
1. Think about your drinking beforehand and plan how you will manage it.
2. Drink slowly, eat while drinking or drink on a full stomach, and make
every other drink (or more) a nonalcoholic beverage.
Adapted from Miller & Munoz, 2005; Vogler & Bartz, 1992.
Limiting your own drinking may help others as well. When
people are tempted to drink too much, their main reason for stopping is that “other people were quitting and deciding they’d had
enough” ( Johnson, 2002).
Treatment
Treatment for alcohol dependence begins with sobering up the
person and cutting off the supply. This phase is referred to as
detoxification (literally, “to remove poison”). It frequently produces all the symptoms of drug withdrawal and can be extremely
unpleasant. The next step is to try to restore the person’s health.
Heavy abuse of alcohol usually causes severe damage to body
organs and the nervous system. After alcoholics have “dried out”
and some degree of health has been restored, they may be treated
with tranquilizers, antidepressants, or psychotherapy. Unfortunately, the success of these procedures has been limited.
One mutual-help approach that has been fairly successful is
Alcoholics Anonymous (AA). AA takes a spiritual approach while
acting on the premise that it takes a former alcoholic to understand and help a current alcoholic. Participants at AA meetings
admit that they have a problem, share feelings, and resolve to stay
“dry” one day at a time. Other group members provide support for
those struggling to end dependency. (Other “12-step” programs,
such as Cocaine Anonymous and Narcotics Anonymous use the
same approach.)
Detoxification In the treatment of alcoholism, the withdrawal of the
patient from alcohol.
210
CHAPTER 6
Eighty percent of those who remain in AA for more than 1 year
get through the following year without a drink. However, AA’s
success rate may simply reflect the fact that members join voluntarily, meaning they have admitted they have a serious problem
(Morgenstern et al., 1997). Sadly, it seems that alcohol abusers will
often not face their problems until they have “hit rock bottom.” If
they are willing, though, AA presents a practical approach to the
problem (Vaillant, 2005).
Other groups offer a rational, nonspiritual approach to alcohol
abuse that better fits the needs of some people. Examples include
Rational Recovery and Secular Organizations for Sobriety (SOS).
Other alternatives to AA include medical treatment, group therapy, and individual psychotherapy (Buddie, 2004). There is a
strong tendency for abusive drinkers to deny they have a problem.
The sooner they seek help, the better.
Hallucinogens — Tripping
the Light Fantastic
Marijuana is the most popular illicit drug in America (SAMHSA,
2005). The main active chemical in marijuana is tetrahydrocannabinol (tet-rah-hydro-cah-NAB-ih-nol), or THC for short.
THC is a mild hallucinogen (hal-LU-sin-oh-jin: a substance that
alters sensory impressions). Other hallucinogenic drugs include
LSD and PCP.
LSD and PCP
The drug LSD (lysergic acid diethylamide, or “acid”) is perhaps
the best-known hallucinogen. Even when taken in tiny amounts,
LSD can produce hallucinations and psychotic-like disturbances
in thinking and perception. Two other common hallucinogens are
mescaline (peyote) and psilocybin (“magic mushrooms,” or
“shrooms”). Incidentally, the drug PCP (phencyclidine, or “angel
dust”) can have hallucinogenic effects. However, PCP, which is an
anesthetic, also has stimulant and depressant effects. This potent
combination can cause extreme agitation, disorientation, violence — and too often, tragedy. All the hallucinogens, including
marijuana, typically affect neurotransmitter systems that carry
messages between brain cells ( Julien, 2005).
Marijuana
Marijuana and hashish are derived from the hemp plant Cannabis
sativa. Marijuana (“pot,” “grass,” “Ganja,” “MJ”) consists of the
dried leaves and flowers of the hemp plant. Hashish is a resinous
material scraped from Cannabis leaves. Marijuana’s psychological
effects include a sense of euphoria or well-being, relaxation, altered
time sense, and perceptual distortions. At high dosages, however,
paranoia, hallucinations, and delusions can occur (Ksir, Hart, &
Ray, 2006). All considered, marijuana intoxication is relatively
subtle by comparison to drugs such as LSD or alcohol. Despite
this, driving a car while high on marijuana can be extremely hazardous. As a matter of fact, driving under the influence of any
intoxicating drug is dangerous.
No overdose deaths from marijuana have been reported. However, marijuana cannot be considered harmless. Particularly worrisome is the fact that THC accumulates in the body’s fatty tissues,
especially in the brain and reproductive organs. Even if a person
smokes marijuana just once a week, the body is never entirely free of
THC. Scientists have located a specific receptor site on the surface of
brain cells where THC binds to produce its effects ( Figure 6.14).
•
Figure 6.14 This thin slice of a rat’s brain has been washed with a radioactive
•THC-like
drug. Yellowish areas show where the brain is rich in THC receptors. In addi-
Artists have tried at times to capture the effects of hallucinogens. Here, the artist
depicts visual experiences he had while under the influence of LSD.
tion to the cortex, or outer layer of the brain, THC receptors are found in abundance
in areas involved in the control of coordinated movement. Naturally occurring
chemicals similar to THC may help the brain cope with pain and stress. However,
when THC is used as a drug, high doses can cause paranoia, hallucinations, and dizziness (Julien, 2005). (From “Marijuana and the Brain,” Science News, vol. 143.)
States of Consciousness
211
Long-Term Health Risks
These receptor sites are found in large numbers in the cerebral cortex, which is the seat of human consciousness (Julien, 2005). In addition, THC receptors are found in areas involved in the control of
skilled movement. Naturally occurring chemicals similar to THC
may help the brain cope with pain and stress. However, when THC
is used as a drug, high dosages can cause paranoia, hallucinations, and
dizziness.
Marijuana’s long-term effects include the following health risks:
1. Marijuana smoke contains 50 percent more cancer-causing
hydrocarbons and 16 times more tar than tobacco smoke
does. Thus, smoking several joints a week may be the equivalent of smoking a dozen cigarettes a day. In regular users,
marijuana increases the risk of a variety of cancers, including
prostate and cervical cancer (Hashibe, 2005).
2. Marijuana temporarily lowers sperm production in males,
and users produce more abnormal sperm. This could be a
problem for a man who is marginally fertile and wants to
have a family (Schuel et al., 1999).
3. In experiments with female monkeys, THC causes abnormal
menstrual cycles and disrupts ovulation. Other animal studies show that THC causes a higher rate of miscarriages and
that it can reach the developing fetus. As is true for so many
other drugs, it appears that marijuana should be avoided during pregnancy.
4. THC can suppress the body’s immune system, increasing the
risk of disease.
5. In animals, marijuana causes genetic damage within cells
of the body. It is not known to what extent this happens in
humans, but it does suggest that marijuana can be detrimental to health.
6. Activity levels in the cerebellum are lower than normal in
marijuana abusers. This may explain why chronic marijuana
users tend to show some loss of coordination (Volkow et al.,
1996).
7. There is some evidence that THC damages parts of the brain
important for memory (Chan et al., 1998).
8. Children whose mothers smoked marijuana during pregnancy show lowered ability to succeed in challenging,
goal-oriented activities (Fried & Smith, 2001; Noland et al.,
2005).
Dangers of Marijuana Use
Does marijuana produce physical dependence? Yes, according to
recent studies (Lichtman & Martin, 2006). Frequent users of
marijuana find it very difficult to quit, so dependence is a risk
(Budney & Hughes, 2006). But marijuana’s potential for abuse lies
primarily in the realm of psychological dependence, not physical
addiction.
For about a day after a person smokes marijuana, his or her
attention, coordination, and short-term memory are impaired
(Pope, Gruber, & Yurgelun-Todd, 1995). Frequent marijuana users
show small declines in learning, memory, attention, and thinking
abilities (Solowij et al., 2002). When surveyed at age 29, nonusers
are healthier, earn more, and are more satisfied with their lives
than people who smoke marijuana regularly (Ellickson, Martino,
& Collins, 2004).
People who smoke five or more joints a week score 4 points
lower on IQ tests. This is enough to dull their learning capacity. In
fact, many people who have stopped using marijuana say they quit
because they were bothered by short-term memory loss and concentration problems. Fortunately, IQ scores and other cognitive
measures rebound in about a month after a person quits using
marijuana (Grant et al., 2001). In other words, people who smoke
dope may act like dopes, but if they quit, there’s a good chance
they will regain their mental abilities.
Although much is still unknown, marijuana appears to pose a
wide range of health risks. Only future research will tell for sure
“what’s in the pot.”
Courtesy of Dr. Lester Grinspoon/Harvard Medical School
A Look Ahead
An outdated antimarijuana poster demonstrates the kind of misinformation that
has long been attached to this drug. Research has finally begun to sort out what
risks are associated with use of marijuana.
Of the many states of consciousness we have discussed, dreaming
remains one of the most familiar — and the most surprising. Are
there lessons to be learned from dreams? What personal insights
lie hidden in the ebb and flow of your dream images? Let’s find out
in the upcoming Psychology in Action section.
Hallucinogen A substance that alters or distorts sensory impressions.
CHAPTER 6
K NOW LED G E B U I L D E R
Psychoactive Drugs
RECITE
1. Addictive drugs stimulate the brain’s reward circuitry by affecting
a. neurotransmitters
b. alpha waves
c. tryptophan levels
d. delta spindles
2. Which of the drugs listed below are known to cause a physical
dependence?
a. heroin
b. morphine
c. codeine
d. methadone
e. barbiturates
f. alcohol
g. marijuana
h. amphetamines
i. nicotine
j. cocaine
k. GHB
3. Amphetamine psychosis is similar to extreme __________________,
in which the individual feels threatened and suffers from delusions.
4. Cocaine is very similar to which of the following in its effects on the
central nervous system?
a. Seconal
b. codeine
c. Cannabis
d. amphetamine
5. Drug interaction is a special danger when a person combines
a. marijuana and amphetamine
b. barbiturates and alcohol
c. alcohol and cocaine
d. marijuana and THC
6. College students may overdrink as they try to keep up with how
much they falsely imagine that their peers drink. T or F?
7. Treatment for alcohol dependence begins with sobering up the person and cutting off the supply. This is referred to as
a. “hitting bottom”
b. the crucial phase
c. detoxification
d. clinical anhedonia
REFLECT
Critical Thinking
8. The U.S. government, which helps fund antismoking campaigns
and smoking-related health research, also continues to subsidize
tobacco growers. Can you explain this contradiction?
9. Why do you think there is such a contrast between the laws regulating marijuana and those regulating alcohol and tobacco?
Relate
What legal drugs did you use in the last year? Did any have psychoactive
properties? How do psychoactive drugs differ from other substances in
their potential for abuse?
Answers: 1. a 2. All of them do 3. paranoia 4. d 5. b 6. T 7. c 8. Neither
can we. 9. Drug laws in Western societies reflect cultural values and historical patterns of use. Inconsistencies in the law often cannot be justified on the basis of pharmacology, health risks, or abuse potential.
212
PSY C HO L O GY IN A CT ION
Exploring and Using Dreams
Gateway Question: How can dreams be used
to promote personal understanding?
No matter what theory of dreaming we favor,
dreams can be thought of as a message from
yourself to yourself. Thus, the way to understand dreams is to remember them, write
them down, look for the messages they contain, and become deeply acquainted with your
own symbol system. Here’s how:
How to Catch a Dream
1. Before going to sleep, plan to remember
your dreams. Keep a pen and paper or a
recorder beside your bed.
2. If possible, arrange to awaken gradually
without an alarm. Natural awakening
almost always follows soon after a REM
period.
3. If you rarely remember your dreams, you
may want to set an alarm clock to go
off an hour before you usually awaken.
4.
5.
6.
7.
Although less desirable than awakening naturally, this may let you catch a
dream.
Upon awakening, lie still and review the
dream images with your eyes closed. Try
to recall as many details as possible.
If you can, make your first dream record
(whether by writing or by recording)
with your eyes closed. Opening your
eyes will disrupt dream recall.
Review the dream again and record
as many additional details as you can
remember. Dream memories disappear
quickly. Be sure to describe feelings as
well as the plot, characters, and actions
of the dream.
Put your dreams into a permanent
dream diary. Keep dreams in chronological order and review them periodically. This procedure will reveal
recurrent themes, conflicts, and emo-
tions. It almost always produces valuable
insights.
8. Remember, a number of drugs suppress
dreaming by interfering with REM sleep
( Table 6.6).
•
Dream Work
At one time or another almost everyone has
had a dream that seemed to have deep meaning (Rock, 2004). Exploring everyday dream
life can be a source of personal enrichment
and personal growth (Cartwright & Lamberg, 1992). What strategies do psychologists
use to interpret dreams? Let’s start with Sigmund Freud’s pioneering approach.
To unlock dreams, Freud identified four
dream processes, or mental filters, that disguise the meanings of dreams. The first is
condensation, in which several people,
objects, or events are combined into a single
dream image. A dream character that looks
States of Consciousness
•
Table 6.6 Effects of Selected Drugs
on Dreaming
Drug
Effect on
REM Sleep
Alcohol
Decrease
Amphetamines
Decrease
Barbiturates
Decrease
Caffeine
None
Cocaine
Decrease
Ecstasy
Decrease (by interrupting sleep)
LSD
Slight increase
Marijuana
Slight decrease or
no effect
Opiates
Decrease
Valium
Decrease
Courtesy of Maryanne Mott
like a teacher, acts like your father, talks like
your mother, and is dressed like your employer
might be a condensation of authority figures
in your life.
Displacement is a second way of disguising dream content. Displacement may cause
important emotions or actions of a dream to
be redirected toward safe or seemingly unimportant images. Thus, a student angry at his
parents might dream of accidentally wrecking
their car instead of directly attacking them.
How would you try to find the meaning of this
dream? A traditional approach is to look for symbolic
messages, as well as literal meanings. If you find
yourself wearing a mask in a dream, for instance,
it could relate to important roles that you play at
school, work, or home. It could also mean that you
want to hide or that you are looking forward to a
costume party. However, to accurately interpret a
dream, it is important to learn your own “vocabulary” of dream images and meanings. Keeping a
dream diary is the first step toward gaining valuable
insights.
A third dream process is symbolization.
As mentioned earlier, Freud believed that
dreams are often expressed in images that
are symbolic rather than literal. That’s
why it helps to ask what feelings or ideas a
dream image might symbolize. Let’s say, for
example, that a student dreams of coming to
class naked. A literal interpretation would
be that the student is an exhibitionist. A
more likely symbolic meaning is that the
student feels vulnerable or unprepared in
the class.
Secondary elaboration is the fourth
method by which dream meanings are disguised. Secondary elaboration is the tendency to make a dream more logical and to
add details when remembering it. The fresher
a dream memory is, the more useful it is likely
to be.
Looking for condensation, displacement,
symbolization, and secondary elaboration
may help you unlock your dreams. But there
are other techniques that may be more effective. Dream theorist Calvin Hall (1974) preferred to think of dreams as plays and the
dreamer as a playwright. Although Hall
points out that dream images and ideas tend
to be more primitive than waking thoughts,
much can be learned by simply considering
the setting, cast of characters, plot, and emotions
portrayed in a dream.
Another dream theorist, Rosalind Cartwright, suggests that dreams are primarily
“feeling statements.” According to her, the
overall emotional tone (underlying mood) of
a dream is a major clue to its meaning (Cartwright & Lamberg, 1992). Is the dream comical, threatening, joyous, or depressing? Were
you lonely, jealous, frightened, in love, or
angry?
Because each dream has several possible
meanings or levels of meaning, there is no
fixed way to work with it. Telling the dream
to others and discussing its meaning can be a
good start. Describing it may help you relive
some of the feelings in the dream. Also, family members or friends may be able to offer
interpretations to which you would be blind.
Watch for verbal or visual puns and other
playful elements in dreams. For example, if
you dream that you are in a wrestling match
and your arm is pinned behind your back, it
may mean that you feel someone is “twisting
your arm” in real life.
The meaning of most dreams will yield to
a little detective work. Try asking a series of
213
questions about dreams you would like to
understand:
Probing Dreams
1. Who was in the dream? Were there
humans, animals, or mythical characters?
Do you recognize any of the characters?
2. What social interactions were taking
place? Were those interactions friendly?
Aggressive? Sexual?
3. What activities were taking place? Were
they physical activities or not?
4. Was there striving? Was the striving successful or not?
5. Was the dream about good fortune or
misfortune?
6. What emotions were present in the
dream? Was there anger, apprehension,
confusion, happiness, or sadness?
7. What were the physical surroundings
like? What was the setting? Were there
any physical objects present? (Adapted
from the Hall-Van de Castle system of
dream content analysis; Domhoff, 2003.)
If you still have trouble seeing the meaning
of a dream, you may find it helpful to use a
technique developed by Fritz Perls. Perls, the
originator of Gestalt therapy, considered
most dreams a special message about what’s
missing in our lives, what we avoid doing, or
feelings that need to be “re-owned.” Perls
believed that dreams are a way of filling in
gaps in personal experience (Perls, 1969).
An approach that Perls found helpful is to
“take the part of ” or “speak for” each of the
characters and objects in the dream. In other
words, if you dream about a strange man standing behind a doorway, you would speak aloud
to the man, then answer for him. To use Perls’
method, you would even speak for the door,
perhaps saying something like, “I am a barrier.
I keep you safe, but I also keep you locked
Dream processes Mental filters that hide the
true meanings of dreams.
Condensation Combining several people,
objects, or events into a single dream image.
Displacement Directing emotions or actions
toward safe or unimportant dream images.
Symbolization The nonliteral expression of
dream content.
Secondary elaboration Making a
dream more logical and complete while
remembering it.
214
CHAPTER 6
inside. The stranger has something to tell you.
You must risk opening me to learn it.”
A particularly interesting dream exercise is
to continue a dream as waking fantasy so that
it may be concluded or carried on to a more
meaningful ending. As the world of dreams
and your personal dream language become
more familiar, you will doubtless find many
answers, paradoxes, intuitions, and insights
into your own behavior.
Using Your Dreams
It is possible to learn to use dreams for our
own purposes. For example, as mentioned
previously, nightmare sufferers can use imagery rehearsal to modify their own nightmares
(Germain et al., 2004; Krakow & Zadra,
2006). Similarly, it is possible to use your
dreams to enhance creativity (Stickgold &
Walker, 2004).
Dreams and Creativity
History is full of cases where dreams have been
a pathway to creativity and discovery. A striking example is provided by Dr. Otto Loewi, a
pharmacologist and winner of a Nobel Prize.
Loewi had spent years studying the chemical
transmission of nerve impulses. A tremendous
breakthrough in his research came when he
dreamed of an experiment 3 nights in a row.
The first 2 nights he woke up and scribbled the
experiment on a pad. But the next morning, he
couldn’t tell what the notes meant. On the
third night, he got up after having the dream.
This time, instead of making notes he went
straight to his laboratory and performed the
crucial experiment. Loewi later said that if the
experiment had occurred to him while awake
he would have rejected it.
Loewi’s experience gives some insight into
using dreams to produce creative solutions.
Inhibitions are reduced during dreaming,
which may be especially useful in solving
problems